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Seer iavens tints Nye tse

THOMAS LINCOLN

CASEY

LIBRARY

1925

76/ / i Ent,

51st CONGRESS, } HOUSE OF REPRESENTATIVES. van Doc. 1st Session. No. 269.

U.S. DEPARTMENT OF AGRICULTURE.

Meet REPORT

OF THE

UNITED STATES

ENTOMOLOGICAL COMMISSION,

BEING A REVISED AND ENLARGED EDITION OF Buuuetin No. 7,

ON

INSECTS INJURIOUS TO FOREST AND SHADE TREES.

BY

ALPHEUS S. PACKARD, M. D., Pu. D. yi]

WITH WOOD-OUTS AND 38 PLATES,

WASHINGTON: GOVERNMENT PRINTING OFFICE. 1890.

JOINT RESOLUTION AUTHORIZING THE PRINTING OF TWO THOUSAND COPIES OF THE FIFTH REPORT OF THE UNITED STATES ENTOMO- LOGICAL COMMISSION.

The following resolution, originating in the House of Representa- tives, was concurred in by the Senate, July 6, 1882:

Resolved by the House of Representatives (the Senate concurring), That there be printed, for the use of the Department of Agriculture, with necessary illustrations, 2,000 copies of the fifth report of the United States Entomological Commission, being a special report on the insects affecting forest trees.—(See Congressional Record, July 7, 1882.)

II

Tas nw- OF CONTENTS.

Literature of forest entomology, 5—Insects in general, 6—The beetles and borers, 7—Moths and butterflies, 7—Gall-flies, 10—Saw-flies, 12—Plant- lice, 13—Bark-lice, 14—Dipterous or two-winged gall-flies, 14—Insec- tivorous or parasitic insects, 14—Artificial breeding of parasitic and predaceous insects, 16—Coleopterous enemies of borers, 18—Influence of temperature on insect life, 19—Generations or broods, 19—Hiberna- tion stage, 23—Diseases of trees produced by the attacks of insects, 24— The appearance of unusual new growths, 24—The origin of repaired parts from representative indefinite growths is very general, 25—Pre- vention and remedies against forest insects, 27—Borers in shade and ornamental trees, 27—Prevention and remedies against timber-beetles and bark-borers, 28—Insecticides and means of applying them to shade and forest trees, 31—-Paris green and London purple, 31—Insecticides which act by contact, 34—Wood ashes and lime, 34—Coal ashes and coal dust, 35—Pyrethrum, hellebore, sulphur, 35—Alkaline washes, potash lye and soda lye, 35—Alkaline washes, soaps, 35—Petroleum pro- ducts, kerosene, naphtha, 36—Kerosene emulsions, 36—Resin washes, 37—Fumigants, gases, 37—Hydrocyanic acid gas, 38—Insecticide ap- paratus, 38—Devices for applying powders, powder blowers, 383—The Woodason bellows, 39—The Leggett Brothers orchard gun, 39—De- vices for applying liquids, 39—The pump, 39—Hose and bamboo ex- tension rod, 42—Nozzles; the Riley or Cyclone nozzle, 44—The Nixon or Climax nozzle, 46.

CHAPTER I.

PERINAT IOUN HET OWN caries cc nD e vac s2s baloeidentieusdiss eccisintrsema anne ccumes

Affecting the roots, 49—Affecting the trunk, 53—Affecting the ibs and

twigs, 83—Feeding on the buds, 116—Injuring the leaves, 117—Injuring

the seeds (acorns), 215—Insects either habitually or occasionally oc- curring on the oak, 217.

CHAPTER II. SRCCEDS EMIMTIDUG LO\TRE CUB: 4 canis lcian & Ss 2mbhadiegomemen dA od sien alee upolcinefSur alecck

Affecting the trunk, 224—Affecting the leaves, 230—Insects occasionally preying upon the elm, 282.

CHAPTER III:

aCSLe ANIUTIOUS.1O URE TACKOTY. 22 = 3 ==). Ke an gucpathibacceshs'sse os. +secSeces-deeacs Injuring the trunk and branches, 285—Affecting the bark, 298—A ffecting the leaves, 299—Affecting the fruit, 326 —Other species occurring on the

hickory, 328. Insects injurious to the black walnut . ..2 224.2220. 22 cnc nns cece en cnn nee cece cece Affecting the trunk, 329—Other species occurring on the black walnut, 336.

III

48

224

285

IV TABLE OF CONTENTS.

Insects injurious to the butternut... . 2 5. occe oo oon coon wo cc ee wcenes dace cece corn Affecting the trunk and limbs, 337—Affecting the leaves, 338—Other species living on the butternut, 342. Tasects tnjurious to the chestnit.....05 2-20 cacecs cumeee dee aenicnsseemnenedascase Affecting the trunk and limbs, 343—Affecting the leaves, 344—Affecting the fruit, 350—Other species preying on the chestnut, 353.

CHAPTER IV.

Insects injurious to the locust treé.... 2200 cose cove canes cones cocces conccecorans Affecting the trunk, 355—Affecting the leaves, 361—Other insects feeding on the locust, 372.

CHAPTER V.

Insects injurious to the different species of maple .....- ceee eevee ceccee cere ennnes Affecting the trunk, 374—Boring in the twigs, 391—Affecting the leaf-buds, 392—Affecting the leaves, 392—Other insects occurring on the maple,

424.

CHAPTER VI.

Insects injurious to the cottonwood .2 2 22. St 2csc\o scene ce ene eec sees eee tenes celecas Affecting the roots, 426—Affecting the trunk and branches, 426—Affecting the leaves, 428. UMgects tjuUntoUus: CONE MOPLAN pe aoe cn (estes solece aye nse) «oo eia eee eee eee ee ate Affecting the trunk, 435—Affecting the leaves, 445—Other insects feeding on the poplar, 472. Insects injurious to the bass-wood or linden tree. ..-. .--- --- 22 ---- eee ene ee eee Affecting the trunk, 474—Affecting the leaves, 475—Other insects living on the linden, 480. CHAPTER VII.

dnsecte anjursous to the, Ci Oh .2-5 566-5 dacaaep acest) sabe nae as seer cape ee eeeeee Injuring the trunk, 483—Affecting the leaves, 486—Other species occurring on the birch, 514.

CHAPTER VIII.

Tnsects injurious tothe beeeh ss si. 103 2 3 aco ae eae woes tute cae eaeleeiem sea eae Affecting the trunk, 515—Affecting the leaves, 515—Other insects occurring on the beech, 519.

CHAPTER IX.

Insects injurious to the wild cherry, wild plum, the thorn, crab-apple and mountain ash.

Insects affecting the wild cherry: Affecting the trunk, 521—Affecting the leaves, 522—Other insects, 529.

Insects affecting the wild plum: Feeding on the leaves, 530—Feeding on the fruit, 530—Other insects, 531.

Insects affecting the service-berry or June berry, 531.

Insects affecting the wild thorn: Affecting the leaves, 532—Other insects, 535. i

Insects injurious to the crab-apple: Affecting the leaves, 537.

Insects injurious to the mountain ash: Affecting the leaves, 537—Other in- sects, 539.

CHAPTER X.

Uasenta tnjurtous to the' USN... 5 soe ecen weno ne neon ase ees teases ayon chan cane aman Affecting the trunk and branches, 540—Affecting the leaves, 544—Other in- sects occurring on the ash, 555.

355:

374

426.

435.

474

483.

515.

52k

540

TABLE OF CONTENTS.

CHAPTER XI.

MAIBEUIA EMP UINOUSLTONULE WEL LOW or ae cio ct as Soa Nae sooo doce, co cee weleeds Sadeceieeeod« Affecting the trunk, 557—Injuring the leaves, 559—Other insects occurring on the willow, 596.

CHAPTER XII.

RBUCES TRIUIWOUR CO URE RUCKUEITY some - <5 vec cme wnce ences scacec soness -onece cone Injuring the leaves, 602—Boring in the trunk, 610—Cecidomyidous hack- berry galls, 612—Hackberry Psyllide, 614.

CHAPTER XIII.

Insects preying upon the alder. ...-~. .---+. -- +--+ - 2-202 see 2 nee eee eee eee ee Boring in the trunk, 623—Injuring the leaves, 625—Other insects of the alder, 636. Insects injurious to the hazel: Feeding on the leaves, 637—Affecting the nuts, 641—Other insects, 641.

CHAPTER XIV.

PRIEECISIENIUTIOUS TONLE) SUCUMONE BELG - ae catseic cos oweieis Gamal ccmiocisweeeealaces seeaes

Boring in the trunk, 643—Eating the leaves, 644—Other insects also occur- ring on the sycamore, 646.

Insects injurious to the hop-hornbeam, or iron-wood, 647.

Insects infesting the water-beech, hornbeam, 650.

Insects injurious to the sassafras, 650.

Insects injuring the honey-locust: Affecting the leaves, 652—Other insects of the honey-locust, 653.

Insects injuring the horse chestnut, or buckeye: Boring in the terminal twigs, 654—Aftecting the leaves, 656.

Insects of the sweet-gum, 657.

Insects injurious to the sour-gum tree, 657.

Insects injurious to the prickly ash: Affecting the trunk and limbs, 659— Eating the leaves, 661.

Insects of the tulip tree, 663.

Insects injurious to the sumach, 664.

Insects injurious to the poison ivy, 665.

Insects affecting the catalpa: Affecting the leaves, 666—Affecting the pods, 666.

Insects injurious to the witch hazel, 668.

Insects i injurious to the magnolia, 669.

Insects injurious to the papaw, 669.

Insects injurious to the tree of heaven, 669.

Insects injurious to the box elder, 669.

Insects injurious to the mesquite, 670.

Insects injurious to the persimmon, 671.

Insects injurious to the California bay or laurel, 671.

Insects affecting the China tree, 671.

Insects injurious to the dogwood, 672.

Insects injurious to the box, 672.

Insects injurious to the black alder, 673.

Insects injurious to the Kentucky coffee tree, 673.

CHAPTER XV.

BME PrN MESORELIO CRE DIRE 2 hoe one a cae ccs tee ws oeda decide ace wee scotes oe en'< Affecting the roots, 675—Affecting the trunk, 676—Affecting the twigs, 735— Affecting the leaves, 756—Other insects occurring on the pine, 809.

601

623

643

VI TABLE OF CONTENTS.

CHAPTER XVI.

Page. ARSE0S WNjUNOUS LO thE EPVUCE ac cern dowree! soe cere) <i winiciel se Malolos e'eieinet a tele ae eae ee 811 Affecting the trunk and branches, 311—Affecting the leaves, 830—Affecting the cones, 854—Other insects of the spruce, 856—Insects injurious to the Rocky Mountain spruce and Douglass spruce, 857. CHAPTER XVII. Insects injurious to the fir tree... 55 Sendtispieetn ose pase eases ae eee eee 861 Affecting the trunk, 861—Affecting the leaves, 862—Other insects of the fir, 869.

CHAPTER XVIII.

Insects injurious to the hemlock and larch .-...---.. <----.'.2-2-- ---+ -- 0025 --- == 871 Injuring the trunk, 871—Affecting the leaves, 873. Insects injurious to the larch or tamarack: Affecting the leaves, 879—Other insects, 903. CHAPTER XIX. TaRectsnjurtous tO they UNDE? a5.5- 2a so emncins ee ise es) aoe neni cee pee eee 904 Affecting the trunk, 904—Affecting the leaves, 907. Insects injurious to the common juniper, 910.

CHAPTER XX.

Insects injurious to the cedar and cypress .... .. 220. .- =~ 25 ©. secs cons ence wa5- wane - 917 Insects injurious to the cedar, 917. Insects injurious to the cypress, 921. Insects injurious to the Sequoia gigantea, 922.

EXPLANATIONS! LO UPDATES 2 2/oc2-s a2 cbc Sone te eee Oe eee oe ce tee ae eee ee mae INDICES OF INSECTS, PLANTS, AND AUTHORS QUOTED ........-.--... --0. 929, 947, 953

LETTER OF SUBMITTAL.

DEPARTMENT OF AGRICULTURE, DIVISION OF ENTOMOLOGY, Washington, D. C., December 26, 1887. Str: In accordance with the act of Congress approved March 3, 1881, which provided that the reports of the United States Entomolog- ical Commission be made to the Commissioner of Agriculture, I have the honor to submit for publication this the fifth and final report of said Commission. This report is on the insects affecting forest trees, by Dr. A. S. Packard, and has been in part written and completed since the termination of the work of the Commission, and while he has been connected with the Division as a special agent. Respectfully, C. V. RILEY, Chief U.S. E. C. Hon. NORMAN J. COLMAN, Commissioner of Agriculture. Vil

vill

MEMBERS OF THE COMMISSION.

C. V. RILEY, Chief. A. S. PACKARD, Secretary. CYRUS THOMAS, Disbursing Agent.

INSECTS INJURIOUS TO FOREST AND SHADE TREES.

PREFACE.

The following report is an enlarged and revised edition of Bulletin 7 of the U.S. Entomological Commission on insects injurious to forest and shade trees, which was published in 1881.

The design of this report is to give to the public, especially those persons interested in forestry and the planting and cultivation of shade trees, a brief summary of what is up to this time known of the habits and appearance of such insects as are injurious to the more useful kinds of trees. It is hoped that such a compendium will be found useful, and lead the reader not only to refer to the works of Harris, Fitch, Walsh, Riley, Le Conte, Horn, LeBaron, Saunders, Lintner, Forbes, and others of our entomologists who have contributed to this neglected branch, but induce him to make careful observations on the habits of destruc- tive forest insects and to carry on experiments as to the best remedies against their insidious attacks. The writer has added notes of obser- vations made during the past twenty-five years in the forests of Maine, New Hampshire, New York, and the woods of Massachusetts, as well as in Colorado, Utah, Montana, Florida, and on the Pacific coast; also a number of original engravings. The aim has been both to present original matter and to bring together from numerous entomological works, reports, and journals all that is of most importance to the prac- tical man. It is hoped that the work in its present form may serve as a convenient synopsis, a starting-point for future more detailed work, as well as a handy book of reference for the use of future observers, and that it will call the attention of the public to a neglected subject, stimulating entomologists, practical foresters, and gardeners to do what they can to add to our knowledge of this department of applied or economic entomology.

A volume could be written on the insects living on any single kind of tree, and hereafter it may be expected that the insect population of the’ oak, elm, poplar, pine, and other trees will be treated of mono- graphically. Certainly there could be no more interesting and profit- able work for the young entomologist.

5 ENT——1 1

2 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

The preservation of our forests and of old and valued shade trees in our cities and towns is a subject of pressing importance, and it is to-be hoped that the Government will foster private work and research in this direction. Next to the wanton destruction of forests by unthinking settlers and shiftless land owners, as well as by fires caused by the sparks of locomotives, the attacks of injurious insects are most widespread and far-reaching. Our forest and shade trees are yearly growing more valuable and indispensable, and at the same time the ravages of in- sects are becoming more widespread and noticeable. The diffusion of a moderate amount of information upon the subject at the present time will attract the notice of the public and lead owners of land to pay a little attention to the subject and do something towards checking the ravages of noxious insects.

In France and Germany private persons, entomologists such as Per- ris in France, and especially Ratzeburg in Germany, have published beautifully illustrated general works of very great interest and value upon forest insects, and their books have done immense service in those countries, where an enlightened government and an intelligent people have felt the importance of building up schools cf forestry and of making laws compelling due efforts towards repressing the more injuri- ous forest insects.

Kaltenbach, in his work entitled ‘‘ Die Pflanzenfeinde aus der Klasse der Insekten,” or the Insect-enemies of Plants, has enumerated, in a closely-printed volume of 848 pages, the species of insects preying upon the different trees and plants, of all sorts, of central Europe. The num- ber of insects found upon some kinds of forest trees is astonishing, though it is to be remembered that all kinds are not equally destructive, the most injurious and deadly forms being comparatively few.

Kaltenbach enumerates 537 species of insects injurious to the oak, and 107 obnoxious to the elm. The poplars afford a livelihood to 264 kinds of insects; the willows yield food to 396 species; the birches har- bor 270 species; the alder, 119; the beech, 154; the hazelnut, 97, and

the hornbeam, 88. Coming to the coniferous trees, as the pine, spruce,

larch, firs, etc., the junipers supply 33 species, while upon the pines, larch, spruce, and firs, collectively, prey 299 species of insects. In France Perris has observed over one hundred species either injurious to, or living upon without being especially injurious to, the maritime pine. These are described in an octavo volume of 532 pages, with numerous plates.

The number as yet known to attack the different kinds of trees in the United States may be seen by reference to the following pages. It is sufficiently large to excite great fears for the future prosperity of our diminished forests, unless the Government interposes, and through the proper channels fosters entomological research in this direction. Our forests, moreover, are much richer in species of trees than those of Eu- rope. We have, without doubt, on the trees corresponding to those of

) | : :

PREFACE. 3

Europe as many destructive species as in Europe. But we have many more shade and forest trees of importance in the eastern United States alone, and when we add to these the forest trees of the western Rocky Mountain plateau and of the Pacific coast, and when we look forward to the attention which must be given in the immediate future to the planting of shade and forest trees on the great plains and in California, the subject of forest entomology assumes still more importance.

The author has here arranged the forest trees in the order of their importance, beginning with the hard-wood or deciduous trees, the oak heading the list, and ending with the coniferous trees; and under each tree he has first described the habits of the insect on the whole most injurious, sometimes merely giving a list of those insects found to be regular parasites of the tree but not specially injurious, though it should be borne in mind that any species of insect may at certain sea- sons so abound as to prove destructive.

In preparing the original bulletin, the author was, for valuable infor- mation regarding the food-trees of a number of beetles hitherto unpub- lished, indebted to Mr. George Hunt, of Providence, R. I, and for aid in collecting specimens he acknowledged the assistance received from Mr. Edwin C. Calder, formerly assistant instructor in chemistry, Brown University, and from Prof. H.C. Bumpus, then a member of the sopho- more class of Brown University.

While preparing the work in its present form the author has been for the last four years connected with the Division of Entomology as a special agent, and matter contained in his reports have been incorpo- rated in this general work. And he takes pleasure in acknowledging the constant aid and sympathy in the work shown by Professor Riley, the United States Entomologist, not only in allowing free and unre- stricted use of specimens, both in his private collection and that which he has generously presented to the Agricultural Department at Wash- ington and to the National Museum, but for the privilege of describing the transformations of a number of species, represented by blown or alcoholic larve, Professor Riley has also freely made over to the author many hitherto unpublished notes of habits and transformations, which have been accumulating for the past twenty years—notes and observa- tions which most persons would naturally prefer to keep or publish in- dependently under theirown names. These especially relate to oak and elm insects, besides others, and are acknowledged in the places where they appear. He alsocontributes an account of the insects of the Celtis.

Professor Riley has also allowed the use of some unpublished draw- ings and a few cuts prepared as Entomologist of the Department of Agriculture for future use.

Thanks are also due to the late S. Lowell Elliott, esq., of Brooklyn, Henry Edwards, esq., of New York, and Professor Riley, as well as to Dr. G. H. Horn, of Philadelphia; Dr. P. R. Uhler, of Baltimore; Dr. J. A. Lintner, State entomologist of New York, Mr. L. O. Howard and

4 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Mr. E. A. Schwarz, assistant entomologists in the National Department of Agriculture, and Mr. D. W. Coquillett, of California, one of Professor Riley’s field agents, for numerous favors in identifying insects, and other aid, and information.

For some of the colored drawings the author is indebted to Mr. Joseph Bridgham, Mr. H. H. Wilder, Prof. H.C. Bumpus, Miss Julia E. Sand- ers, Miss Emily A. Morton, and to the late Dr. J. L. Le Conte for a few colored drawings bequeathed by his father. These are specifically acknowledged in the explanations of the plates. Professor Riley has also had a number of original drawings made by Dr. George Marx, Mr. J. B. Smith, Miss Lillie Sullivan, all of Washington, and others have been made by Mr. Joseph Bridgham, of Providence, R. 1. The artists’ names are mentioned under the cuts in the text.

For aid in collecting specimens in Maine he is indebted to Mr. H. H. Wilder and Master Allen Howe, of Lewiston.

The author is well aware of the short-comings and imperfections in this report. A good deal of time has been expended in unsuccessful at- tempts at raising insects, which has not produced visible results. Up- wards of two hundred descriptions of unidentified larve have been made; those of the oak appear in the appendix, and others are scat- tered through the report. It is hoped that future observations will en- able us to complete these life-histories.. It would have been desirable to have had more and, in some cases, better illustrations.

This report will be sent to all known to be specially interested in en- tomology, and they are respectfully asked to send the author corrections and additions, as undoubtedly a number of species have been omitted from the list of those peculiar to different trees. Such changes could be made in a second, revised edition, should it be called for by the public.

Brown UNIVERSITY,

Providence, R. I., January 2, 1888.

INTRODUCTION.

The subject of Forest Insects is almost a distinct branch of economic entomology, and little special attention has been given to it as yet in this country, owing to the fact that our entomological students have been obliged to concentrate their efforts upon the more destructive garden and field insects.

The special works on this topic are, though few, notable for the extensive research and care with which they have been prepared; hence their permanent value. By far the most important are the voluminous works of Dr. J. T. C. Ratzeburg and those of Perris, Hichhoff, and Kaltenbach, while an excellent general work on forest insects 1s that of Judeich and Nitsche. The following list of works bearing directly on this topic, and indispensable, should be supplemented by the reports and articles of C. V. Riley, J. A. Lintner, J. H. Comstock, S. A. Forbes,

and others:

T. W. Harris Treatise on some of the Insects injurious to Vegetation. Third edition; illustrated. Boston, 1862.

Asa FitcH. Reports (1 to 14) on the noxious, beneficial, and other Insects of the State of New York. Albany, 1856-’70.

V. Koutzar. 4 Treatise on Insects injurious to Gardeners, Foresters, and Farmers. Trans- lated from the German by J. and M. Loudon. London, 1840.

J.T. C. RaTZEBURG. Die Forstinsekten, etc. (Forest Insects). Berlin, 1839, 1840, and 1844. 4 vols. 4to, with many plates.

Die Ichneumonen der Forstinsekten, etc. (Ichneumons of Forest Insects). 3 parts. Berlin, 1844, 1848, and 1852. 4to. Plates.

Die Waldverderber und ihre Feinde (Forest Destroyers and their Enemies). Ber- lin, 1841. 8vo. Sixth edition; 1869.

Die Waldverderbniss oder dauernder Schade, welcher durch Insektenfrass, Schdlen, Schlagen, und Verbeissen an lebenden Waldbdumen entsteht (Forest injury or losses inflicted by insect attacks, etc.). 4to. 2 parts. Berlin, 1866-68, with many colored plates. (A magnificent and most useful work.)

A.S. PACKARD. Guide to the Study of Insects. Ninthedition; 1888. 8vo. New York,

H. Holt & Co. JUDEICH und NitscHE. Lehrbuch der Mittel-Europdischen Foratinsektenkunde. Wien, Part I, 1885. Part II, 1889. 8vo. (Compare also the works of Perris, Taschenberg, Eichhoff, Kaltenbach, Altum, Nordlinger, Henschel, and others.)

While the reader is referred to the ordinary text books for the ele- ments of entomology, the following facts may prove serviceable in connection with the subject of forest entomology:

6 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Insects in geneval.—The term insect is applied to that class of jointed animals (Arthropoda) whose bodies are divided into three regions or sections, called the head, thorax, and hind-body or abdomen. They usually have three pairs of legs attached to the mid-body or thorax, and two pairs of wings. Most insects pass through a series of changes. In the butterfly, for example, after hatching from the egg as a cater- pillar (larva), it transforms to a chrysalis (pupa), finally changing to the imago or winged insect. The insects form a class comprising about 200,000 known species.

They are divided into sixteen orders (not including those which are extinct), as may be seen by the following tabular view copied from the author’s *“‘ Zoology,” which briefly represents the more apparent, super- ficial differences between the groups. The list begins with the lowest, ending with the highest.

Orders of insects now living.

1. Wingless, often with a spring....-......... Thysanura: Spring-tails, ete. 2. Fore wings minute, elytra-like.............. Dermaptera: Earwig. 3. Wings net-veined; fore wings narrow; hind Wilts folded 2 bi 152.e ie see. aemece certs Orthoptera: Locusts, Grassnoppers. 4, Four net-veined wings; mouth-parts adapted for) biting. -\neie es secs ee eeire sees meee Platyptera: White Ants, Bird-lice. 5. Wings net-veined, equal............--..--.-. Odonata: Dragon-flies. 6. Wings net-veined, unequal..................Plectoptera: May flies. 7. Mouth-parts beak-like, but with palpi.---.. Thysanoptera : Thrips. 8. Mouth-parts forming a beak for sucking; no Bal Oh. 2-30 acon me ae 3 eee ee Hemiptera: Bugs.

9. Wings net-veined ; metamorphosis complete. Neuroptera: Lace-winged Fly, ete: 10. Wings long and narrow ; body with a forceps. Mecaptera: Panorpa.

i eWanges not neb-veined <2... 5..=—.c.- see Trichoptera : Caddis-fly. 12. Fore wings sheathing the hinder ones.-... ---- Coleoptera: Beetles.

TS VN LOSS; DATASIUIG = =. -/3 Wao eer Siphonaptera: Fleas.

i One pairot wins. 22a. scenes. eens Diptera: Flies.

15. Four wings and body scaled .............--- Lepidoptera: Butterflies.

16. Four clear wings; hinder pair small; a tongue. Hymenoptera: Bees, Wasps, eto.

Allied to the insects are the myriopods, or centipedes and galley- worms, none of which are injurious to forest or shade-trees, although the smaller kinds of centipedes (Lithobius, etc.), occur under the bark of decayed trees. No spiders or allied forms, comprising the class Arach- nida, are injurious to vegetation, except certain mites (Acarina) whose forms and gall-making habits are peculiar. Many spiders take up their abode in the leaves of shade and forest trees, but none are known to be injurious. The false-scorpions (Chelifer, etc.) often occur under the bark of decayed trees, but they are more useful than otherwise, as they probably devour the smaller wood-boring larve.

The bulk of our destructive forest insects belong to the orders com- prising the beetles, the caterpillars, gall-flies, saw-fly larve, and the bugs. We will mention them in the order of their importance as destructive to shade and forest trees.

INTRODUCTION. 7

The beetles and borers.—The order Coleoptera comprises about 100,000 species of beetles, divided into a large number of families. The beetles are easily recognized by the hard, sheath-like fore wings which pro- tect the hind wings; their jaws are stout and thick, more or less toothed, and adapted for biting.

The iarve of beetles are called ‘“ grubs.” They have been thus characterized in the author’s Guide to the Study of Insects:

The larve, when active and not permanently inclosed (like the Curculio) in the substances which form their food, are elongated, flattened, worm-like, with a large head, well developed mouth parts, and with three pairs of thoracic feet, either horny or fleshy and retractile, while there is often a single terminal prop-leg on the terminal segment and a lateral horny spine. The larvee of the Cerambycide are white, soft, and more or less cylindrical, while those of the Curculionide are footless, or nearly so, and resemble those of the gall-flies, both hymenopterous and dipterous,

The pupz have free limbs, and are either inclosed in cocoons of earth or, if wood-borers, in rude cocoons of fine chips and dust, united by threads or a viscid matter supplied by the insect. * * * Generally, however, the antenne are folded on each side of the clypeus, and the mandibles, maxillw, and labial palpi appear as elongated papille. The wing-pads being small, are shaped like those of the adult Meloe, and are laid upon the posterior femora, thus exposing the meso- and meta- thorax to view. The tarsal joints lie parallel on each side of the middle line of the © body, the hinder pair not reaching to the tips of the abdomen, which ends in a pair of acute, prolonged, forked, incurved, horny hooks, which must aid the pupa in working its way to the surface when about to transform into the beetle.

Most of the destructive kinds belong to the following families : Body of beetle, broad, flat, hard; antenne short, serrated. Larva with head and

first succeeding segment very broad and flat............-....-...---- Buprestidae. Body of beetle more or less cylindrical, with very Jong, slender antenne; larve called “‘borers,” their bodies cylindrical, usually footless .......--. Cerambycide. Small cylindrical beetles, with no snout, called bark-borers; larvz footless, thick, cylindrical, pointed at each end .......... Be ee ee eee Be eas oe, Scolytide. Hard-bodied beetles, called ‘‘weevils,” with a long beak or snout, with jaws at tne end; larvz grub like, footless, thick and fleshy ................-..- Curculionide.,

Moths and butterflies —While a few caterpillars (mostly of the family Aigeriade and the Cossidz) bore into the trunk and branches of trees. the great bulk devour the leaves. Caterpillars are provided with stout, toothed jaws (mandibles) for cutting leaves. They are voracious feeders, as will be seen by the following extract from Mr. L. Trouvelot in Packard’s Guide to the Study of Insects:”

Caterpillars giow very rapidly and consume a great quantity of food. Mr. Trouve- lot gives us the following account of the gastronomical powers of the Polyphemus caterpillar: ‘It is astonishing how rapidly the larva grows, and one who has no experience in the matter could hardly believe what an amount of food is devoured by these little creatures. One experiment which I made can give some idea of it. When the young silk-worm hatches out it weighs one-twentieth of a grain; when ten days old it weighs half a grain, or ten times its original weight; twenty days old it weighs 3 grains, or sixty times its original weight; thirty days old it weighs 31 grains, or 620 times its original weight; forty days old it weighs 90 grains, or 1,800 times its original weight ; fifty-six days old it weighs 207 grains, or 4,140 times its original weight.

When a worm is thirty days old it will have consumed about 90 grains of food; but when fifty-six days old it is fully grown and has consumed not less than one hundred

8 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

and thirty oak leaves weighing three-fourths of a pound; besides this it has drunk not less than one-half an ounce of water. So the food taken by a single silk-worm in fifty-six days equals in weight eighty-six thousand times the primitive weight of the worm. Of this, about one-fourth of a pound becomes excrementitious matter ; 207 grains are assimilated and over 5 ounces have evaporated. What a destruction of leaves this single species of insect could make if only a one-hundredth part of the eggs laid came to maturity. A few years would be sufficient for the propaga- tion of a number large enough to devour all the leaves of our forests.” The Lepidoptera are almost without exception injurious to vegetation, and are among the chief enemies of the agriculturist.

In our descriptions of the larve of Lepidoptera the following points are noticed: Behind the head are twelve segments; the first or pro- thoracic is, in the small leaf-rolling and mining kinds, protected by a ‘‘cervical” or prothoracic shield; there are three thoracic segments, called the prothoracic, mesothoracic or metathoracic, or sometimes the first, second, and third thoracic segments; these correspond to the thorax of the imago or adult butterfly or moth. Behind these are nine distinct abdominal segments; on the eighth is often situated a dorsal hump. Many caterpillars are striped with a dorsal, subdorsal, and lateral lines or bands, moreover, the body in many is provided with warts or tuber- cles bearing a hair or spine; the “lateral ridge” is a broken swelling extending along the sides of the body. The abdominal feet are in cer- tain leaf-miners wanting; or in the span or geometrid worms there are but two pairs; and the last or ‘anal legs” are often broad and large, the better adapted for seizing firm hold of a leaf or twig.

While a few butterflies Jive in the caterpillar state on trees, the fol- lowing brief synopsis gives the most salient characteristics of the families of moths which especially abound on the leaves of shade and forest trees:

Moths of Jarge size; larve with a horn on the eighth abdominal segment... Sphingide. Moths with stout hairy bodies and small heads and broad wings; larvz more or less hairy or with spines; usually spinning silken cocoons..-...--...-.-. Bombycide. Moths of moderate size: stout bodies; shining hind wings; larvz with five pairs of abdominal legs; sometimes semi-loopers.....--.--.---.---..----.------ Noctuide. Moths with slender bodies, broad wings, both pairs colored alike; larve with only two pairs of abdominal legs; span-worms or geometrids ...... ..----. Phalenide. Small moths with narrow, straight fore-wings, the hind wings plain; larve glossy green or pale, the head spotted, and the body more or less striped.... Pyralide. Still smaller moths, the fore-wings more or less oblong; the larve green, with dark heads and cervical shields; not striped; rolling leaves or eating buds... Tortricide. Minute moths with narrow, pointed wings; larvze small, pale greenish, etc., with a darker head and cervical shield; often mining leaves, buds, etc.... .- “.. Tineide.

Forest trees, and especially evergreen trees, support each year hordes of caterpillars, comprising species of different families. In beating the branches of any spruce, fir, larch, poplar, or maple, and especially the oak, a great number and variety of caterpillars are shaken down, and the question arises whether the innumerable host constantly and ordi- narily at work from spring-time to the fall of the leaf in our forest trees are really injurious to the tree. It is not improbable that good

INTRODUCTION. 9

is done to the tree by these voracious beings. The process up to a certain limit may be one of natural and healthy pruning, but there is no certainty that the limit may not at any time be overstepped and destruction ensue. The tree is attacked in a multitude of ways by cater- pillars alone. The buds are eaten by various leaf-rollers (Tortrices), the leaves are mined on the upper and under sides by various Tineids, while the leaves are rolled over in various ways and in various degrees to make shelter for the caterpillars, or they are folded on the edges, or gathered and sewed together by Tineid, Tortricid, and Pyralid larve. The entire leaves are devoured by multitudes of species of larger cater- pillars, belonging especially to the Pyralid, Geometrid, Bombyeid, and Sphingid moths; while certain species prey on the fruit, acorns, nuts, and seeds.

It is a singular fact that of the great family of Owlet or Noctuid moths, of which there are known to be 1,200 species in this country, very few feed on trees, the bulk of them occurring on herbaceous plants and grasses. i

While the smaller caterpillars (Microlepidoptera) feed concealed between the leaves or in the rolls or folds in the leaf, or in the buds, the caterpillars of the larger species feed exposed on or among the leaves. Here they are subject to the attacks of birds and of Ichneumon and Tachina flies, which are constantly on the watch for them. And it is curious to see how nature has protected the caterpillars from observa- tion. While the young of the smaller moths are usually green and of the same hue as the leaves among which they hide, or reddish and brownish if in spruce and fir buds, where they hide at the base of the needles next to the reddish or brownish shoots, the larger kinds are variously colored and assimilated to those of the leaves and twigs among which they feed. Were it not for this they would be snapped up by birds. Of course, the birds devour a good many, and the pry- ing Ichneumons and Tachine lay their eggs in a large proportion, but those which do survive owe their safety to their protective coloration.

Of some twenty or more different species of Geometrid caterpillars which occur on the evergreen trees, some are green and so striped with white that when at rest stretched along a pine needle, they could with difficulty be detected; others resemble in various ways (being brown and warted) the small twigs of these trees; and one is like a dead red leaf of the fir or hemlock. There are several span-worms on the oak, which in color and markings, as well as in the tubercles and warts on the body, resemble the lighter or darker, larger or smaller knotty twigs; this resemblance, of course, is in keeping with the characteristic habit of these worms of holding themselves out stiff and motionless when not feeding.

In an entirely different; way the various kinds of Notodontian cater- pillars, which feed exposed on oak leaves, are protected from observa- tion. They feed on the edges of the leaves, and their bodies are green,

10 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

with reddish brown patches, so that these irregular spots, when the caterpillar is at rest, are closely similar to the dead and sere blotches so frequent on oak ieaves. The same may be said of other kinds feed- ing on the leaves of other forest trees.

While the bodies of those Noctuid caterpillars which feed on herba- ceous plants are smooth, those of the tree-inhabiting Catocala, Homop- tera, and Pheocyma are mottled with brown and ash like the bark of the tree, and provided with dorsal humps and warts assimilated in form and color to the knots and leaf scales on the twigs and smaller branches.

There is thus a close harmony in color, style of markings, shape, and size of the humps and other excrescences of tree-inhabiting caterpil- lars, and it is due to this cause that they are protected from the attacks of their enemies. Mr. Poulton has recently called attention to the fact that caterpillars are extremely liable to die from slight injuries, owing to their soft bodies and thin skins. They can not defend themselves when once discovered. The means of protection are of passive kinds, 7. e., such as render the delicately organized animal] practically invisible on the part of its enemies, and these means vary with each kind of cater- pillar. In this way different kinds of larve can live on different parts of the leaf, the upper or under side, or the edge; on different colored twigs, on those of different sizes, with different kinds of leaf scars, scales, or projections; and thus the tree is divided, so to speak, into so many provinces or sections, within whose limits a particular kind of worm may live with impunity, but beyond which it goes at the peril of its life.

To the Hymenoptera belong the gall-flies and saw-flies, besides bees and ants, and ichneumons.

Gall-flies.—These little creatures produce tumors or galls both in the trunk, branches, but more usually the smaller twigs and leaves of the oak, and rarely other trees. They belong to the family Cynipida, and are described as follows in the writer’s “Guide to the Study of Insects:”

The gall-flies are closely allied to the parasitic Chalcids, but in their habits are plant-parasites, as they live in a gall or tumor formed by the abnormal growth of the vegetable cells, due to the irritation first excited when the egg is laid in the bark or substance of the leaf, as the case may be. The generation of the summer broods is also anomalous, but the parthenogenesis that occurs in these forms, by which im- mense numbers of females are produced, is necessary for the work they perform in the economy of nature. When we see a single oak hung with countless galls, the work of asingle species, and learn how numerous are its natural enemies, it becomes evident that the demand for a great numerical increase must be met by extraordinary means, like the generation of the summer broods of the plant-lice.

The gall-flies are readily recognized by their resemblance to certain Chalcids, but the abdomen is much compressed and usually very short, while the second, or the second and third segments, are greatly developed, the remaining ones being imbri- cated, or covered one by the other, leaving the lined edges exposed. Concealed within these is the long, partially coiled, very slender ovipositor, which arises near the base of the abdomen. [See Plate xv, ovipositor of the gall-fly.] Among other

distinguishing characters, are the straight (not being elbowed) thirteen to sixteen jointed antenne, the labial palpi being from two to four jointed and the maxillary

at

INTRODUCTION. 11

palpi from four to six jointed. The maxillary lobes are broad and membranous, while the ligula is fleshy, and either rounded or square at the end. There is a com- plete costai cell, while the subcostal cells are incomplete. The egg is of large size, and increases in size as the embryo becomes more developed. The larva is a short, thick, fleshy, footless grub, with the segments of the body rather convex. When hatched they immediately attack the interior of the gall, which has already formed around them. Many species transform within the gall, while others enter the earth and there become pupe.

Like the Aphides and certain other insects, the females often repro- duce parthenogenetically, viz, they lay eggs without having paired with males, the latter not being at the time in existence. Thus the late B. D. Walsh * discovered that the autumn brood of a gall-tly (Cynips quer- cus-aciculata) consisted entirely of females which laid eggs, producing the following spring both males and females which were originally re- ferred to a supposed distinct species (Cynips quercus-spongifica). Hence, after several experiments Mr. Walsh declared that ‘‘the agamous autumnal female form of this Cynips (C. q.-aciculata) sooner or later reproduces the bisexual vernal form,” and is thus ‘‘a mere dimorphous female form” of C. q.-spongifica. It was reserved for two other Ameri- can students of the gall-flies to establish the fact that an alternation of generations takes place in these insects. The case is thus stated by Mr. L. O. Howard, in Psyche (111, 329, June 24, 1882).

America may justly claim the credit for the discovery of this most interesting fact of alternation of generations among Cynipids. Riley, in the interjected remarks in his article on ‘‘Controlling Sex in Butterflies” (American Nat., Sept., 1873, v. 7, p. 519), was the first actually to establish the fact beyond all peradventure, asM. Lichten- stein points out; yet Bassett, four months previously (Can. Entomologist, May, 1873, vol. 5, p. 93) had stated, in the following words, the theory which Adler has so fully verified: ‘‘From all the above facts I infer that all our species that are found only in the female sex are represented in another generation by both sexes, and that the two broods are, owing to seasonable differences, produced from galls that are entirely distinct from each other.” In this article Bassett has just missed the actual proof in twoinstances. With Cynips q.-operator he had observed the females of the vernal brood Ovipositing in acorn cups and producing the gall q.-operatola of Riley’s MS.; but he failed to rear the flies from these galls and so missed the complete proof. In the case of C. q.-batatus Bass., he had bred the sexual forms from leaf galls, and the agamic females from twig galls, but had not actually observed the females of the former in the act of ovipositing in the twigs; thus again missing the proof. Riley, however, as he tells us in his published note, succeeded in breeding the agamic females of q.-operator from the acorn galls; thus, in connection with Bassett’s observation of the oviposi- tion, completely establishing the fact of alternation. Sothe credit should bejoint. It is, infact, much like the well-known case of Siredon and Amblystoma, in which the credit should be divided between Baird and Dumeril. Dr. Adler very excusably overlooked this note of Riley’s. Walsh, in his earlier articles, came no nearer the actual state of the case than to prove that two females, formerly described as dis- tinct species, may belong to the same male.

Independently of and subsequently to the work done in the United States, Dr. Adler, of Germany, also discovered and_ satisfactorily

* American Entomologist, ii, 330, October, 1870.

12 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

proved in an extensive and beautifully illustrated memoir* the fact of alternation of generations in a pumber of European species.

In a notice of Adler’s work in the American Naturalist for July, 1881, Professor Riley added that Mr. H. F. Bassett “has, following Adler’s interesting experiments in Europe, suggested the probable di- morphic connection of several of our vernal galls which produce bisexual individuals, with autumnal forms which produce larger asexual flies. Dr. Adler gives a list of nineteen species of Cynipidz in which the oc- currence of dimorphic forms has been proved, giving the names of the agamic forms and the corresponding bisexual forms the latter of which, in all cases, were referred to distinct genera by previous ob- servers.

In this connection should be mentioned the remarkable fact that in certain closely allied species (Aphilotrix seminationis, marginalis, quad- rilineatus and albopunctatus) no alternation of generations seems to occur.

Saw-flies.—These often seriously injure evergreen trees, while they occur on all other trees. There are a large number of species. Their larve resemble caterpillars in appearance and in voracity.. The flies dif- fer from wasps, etc., in the abdomen being broad at the base; the body is somewhat flattened, and the head is wide, while the antenne are not elbowed, and as in Lopbyrus are pectinated in the males, serrated in the females. In the end of the hind body of the female is situated the ‘‘saw” or ovipositor. This consists of two blades, the lower edge of the lower one of which is toothed like a saw, and fits in a groove in the under side of the upper blade; both blades being protected by sheath-

a\9 gt

. 6S Fic. 1.—Saw of a saw-fly (Hylotoma): a, lateral scale; 7, saw; f, gorget. After Lacaze-Duthiers. like stylets. On pressing the end of the abdomen the saw is depressed ; by this movement the saw, which both cuts and pierces, makes a gash

in the soft part of the leaf, where it deposits its eggs. (Fig. 1.)

The Lophyrus of the pine makes a series of punctures on each side of a pine needle; the Nematus of the alder makes from twenty to forty pairs of semicircular punctures in the under side of the midrib of the leaf, while the larch saw-fly inserts her eggs in two alternating rows at the

“*Zeitschrift fiir Wissenschaftliche Zoologie, xxxv, Feb. 1, 1881, pp. 151-246, Pls. x—xii. Dr. Adler’s researches were commenced in 1875, and his first paper appeared in 1877. (Deutsche Entomolog. Zeitschrift, 1877, Heft 1.)

INTRODUCTION. 13

base of the fresh leaves of thenew shoots. The punctures made in the willow by saw-flies of the genus Huura result in the formation of galls or tumors within which the larve live.

The larve strongly resemble caterpillars, hence they are sometimes called “false caterpillars ;” but they have from six to eight pairs of ab- dominal legs, whereas caterpillars have only five pairs. Many kinds (Nematus, etc.) curl the hind body spirally when feeding or at rest. They are usually green, of the color of the leaves upon which they feed, with lines and markings of various colors. They usually molt four times, the last change being the most marked. Most of the larve se- erete silk and spin a tough oval, cylindrical cocoon, in which they hybernate in the larva and often in the pupa state.

Ants and bees.—Auts have not been noticed in the United States to injure trees, but in the tropics species of Gicodoma, or leaf-bearing ants, are very destructive to trees; it is possible that there are species in the Gulf States which may in part defoliate trees.

Bees are of great use in setting the fruit of trees ; little has been ob- served on this point in this country, but without doubt the visits of in- numerable bees to linden trees are of service in “setting” the seed of that tree.

Mr. Lugger* mentions the fact that the seeds of the rock maple, so numerous in the grounds of the Smithsonian Institution, Washington, -D. C., were in 1886 uniformly sterile. He attributed this phenomenon to the inclement weather prevailing during the flowering season, which prevented bees from visiting the flowers.

Plant lice—While many Hemiptera, such as the bugs, destroy many caterpillars, particularly span-worms and leaf-rollers, some of the most annoying and destructive of our forest insects belong to this order. They all take their food by piercing the succulent leaves and stems, or twigs of trees, shrubs, or herbs, often causing them, as in the elm aphis, to crumple up. The species of Psyllidw are very common on the leaves of hard-wood trees, either hopping over the surface or living in leat- galls which are the results of their punctures.

The following account of Aphides or plant-lice is adapted from the writer’s “Guide to the Study of Insects :”

The plant-lice have greenish, flask-shaped bodies, covered with a soft, powdery, bloom ; their antennz are five to seven-jointed, with a three-jointed beak, and legs with two-jointed tarsi. The males and females are winged, and also the last brood of asexual individuals, while the early summer brood are wingless. The-abdomen is thick and rounded, and in Aphis and Lachnus provided with two ‘‘honey tubes” for the passage of a sweet fluid secreted from the stomach.

In theearly autumn the colonies of plant-lice are composed of both male and female individuals; these pair, the males then die, and the females begin to deposit their eggs, after which they also die. Early in the spring, as soon as the leaves begin to unfold, the eggs are hatched, and the young lice begin to suck the sap, and soon be- gin to bring forth young, which develop by a budding process within the body of the

*Entomologica Americana, ii, 89.

14 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

parent. A second generation of sexless individuals thus results, which is succeeded by a third, fourth, fifth, and even a ninth generation, the process being only termi- nated by the approach of cold weather, when a last brood of males and females ap- pear. By this anomalous, asexual mode of reproduction, a single Aphis may become the parent of millions of young.

Certain plant-lice occur on the roots of plants, others on the stems or twigs; others.

puncture leaves, causing them to roll or crumple, or to form galls. Ants are fond of

the sweet excretions from the ‘‘ honey tubes,” and often keep them captive in their nests like herds of cattle. The maggots of Syrphus flies, lady-birds (Coccinella), and the larve of the lace-winged fly, besides small ichneumons, destroy great numbers of them and keep them within due limits.

To the plant-lice family belong the species of Adelges and Chermes which produce. ~

cone-like swellings on the new-grown twigs of spruce; alsc of Pemphigus, which pro- duce gall-like swellings on poplars, etc.

Bark-lice.—In the species of Coccidaw, the males alone are winged, having but a single pair, while the females are wingless, scale-like and do great damage by puncturing the bark of trees.

Dipterous or two winged gall-flies.—Maples, wild plums, poplars, and other trees have numerous leaf:-galls of varied form made by little gnat- like flies belonging to the dipterous family Cecidomyide. These flies. are minute, most of them smaller than a mosquito. The females lay their eggs in the stems, leaves, and buds of various plants and trees, thus producing galls, a common example being the willow dipterous gall-fly (Cecidomyia strobiloides). There are thirteen other species found by Mr. Walsh to raise galls on eight different kinds-of willow, the dif- ferent kinds of galls being readily distinguished, while the flies them- selves and their maggots are closely similar. The maggots of the Cecidomyians are usually minute orange, pinkish, or yellowish worms without feet, and with the body pointed at each end.

Insectivorous or parasitic insects.— While the undue increase of forest insects is largely prevented by insectivorous birds, their numbers are especially reduced by the attacks of parasitic or carnivorous insects. Of these the most efficient are the ichneumon flies, which are wasp- like insects forming a large group of the order Hymenoptera, belonging to the families [chneumonide, Proctotrupide, and Chalcidide. Of the ichneumons there are probably from 4,000 to 5,000 species. Many of

the species of Proctotrupide oviposit in the eggs of Lepidoptera and of -

dragon flies, ete. The largest species belong to the first-named family. They are recognized by their long, slender body and long, external ovipositor. The larva is like the maggot of a bee or wasp, being foot- less, soft, and white, and with a smaller head.

“When about to enter the pupa state the larva spins a cocoon, consisting in the larger species of an inner dense case and a looser, thinner outer covering, and escapes as a fly through the skin of the caterpillar. The cocoons of the smaller genera, such as Cryptus and Microgaster, may be found packed closely in considerable numbers, side by side, or sometimes placed upright within the body of cater- pillars.’”*

* Packard’s ‘Guide to the Study of Insects,” p, 193.

7

PARASITIC INSECTS.

Fig. 2 represents the mode of oviposition by an unknown ichneumon observed by us in Providence. The egg (a) was laid on the head, and the larva soon hatching, bored under the skin, entering the body so as finally to disappear out of sight.

The eggs are laid either within or on the outside of the body of the host, usually some caterpillar.

A special account of the mode of egg-lay- ing of an European ichneumon (Paniscus cephalotes) is given by Mr. E. B. Poulton in the Transactions of the Entomological So- ciety of London, 1886, page 162. It laid 14 eggs on the caterpillar it selected as its host, firmly attaching them to its skin, most of them in the sutures between the segments

15

Fic. 2.—Head of a Noctuid cater-

pillar on the hickory, containing a freshly-hatched ichneumon larva. A, d, egg-shell of the ichneumon on the caterpillar’s head, the larva (e) having bored into the protho- racic segment of its host. B, as the host appears ten minutes later, the egg-shell having dropped off. The prothoracic segment has contracted and the head has be- come swollen, while the posterior part of the caterpillar’s head has concealed the opening of the lar- val parasite seen at A,e. Gissler, del.

on the sides of the body.

“It is probable that an excess of ova is generally laid, for a small proportion do not develop, and the way in which they are attached in small groups insures that of those that do develop a large proportion of the larve are so crowded by the others that they die at an early stage, as has been also previously observed. If too large a number were laid and all developed, it is obvious that none could arrive at ma- turity; but this is obviated in the manner described above, and it is partly brought about by the limited space on the circumference of the larva attacked. This space, of course, varies with the size of the lat- ter, and it is more quickly filled in the rapid development of the para- sites upon small than upon large larve; so that, if they are too numer- ous, crowding ensues earlier, and with more fatal results in the former than in the latter case. Thus the smaller surface may compensate for the less amount of food, and may itself insure that the parasites reach maturity.” The ichneumon lays a smaller number of eggs on small caterpillars than on large ones, and yet lays more than can develop in all cases, ‘“‘the eggs being laid in such a way that crowding results if ali or nearly all develop; so that the chance of the eggs being sterile is obviated on the one hand and of the parasitic larve dying immature on the other.”

The larva of the ichneumon does not attack the solid or vital parts of its host, but absorbs the blood and other fluids of the body. Mr. Poulton thinks that the motive force which drives the blood from the body of the host into the digestive tract of the parasite is entirely supplied by the contracted body-walls of the former.

Many ichneumons are polyphagous, 7. ¢., live in insects of widely differ- ent species, and those of different orders.* Others confine their attacks

*This and tae following remarks on ichneumons are taken mainly from Judeich and Nitsche’s Lehrbuch der Mittel-Europiiischen Forstinsektenkunde.

16 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

to a single species. Most ichneumons have but a single generation; afew are double-brooded. In Germany, Ratzeburg observed a brood of Microgaster globatus early in May, and another early in August. Though there may be two broods of the hosts, there is, as a rule, but a single brood of ichneumons. Ratzeburg, indeed, found that certain ichneumons of saw-fly larve imitated the habit of the latter of living more than a year, 7. é., they did not develop until the greater number of saw-flies kad issued from the belated cocoons. On the other hand Pteromalus puparum undergoes an extraordinarily rapid growth; it stings early in June the chrysalids of Vanessa polychloros, and by the middle of July the adults appear. Teleas ovulorum requires only four to six weeks to develop; it however flies somewhat later, so as to find the suitable objects on which to lay its eggs.

[chneumons rarely develop in adult insects, but certain Braconids infest Coccinella beetles. The small Chalcids, i. e., Pteromali, mostly inhabit the tender pup of bark-boring beetles and leaf-rollers.

Among the smaller ichneumons several females usually inhabit a single host, while from 600 to 700 individuals of Pteromalus puparuwm may inhabit a single chrysalid, and 1,200 Apanteles a Sphinx larva.

Most ichneumons develop within their hosts, but many species of Chaleids live on the outside and suck the blood of their host. The ichneumon larve living within their hosts often undergo the most remarkable transformation of their mouth-parts. In Microgaster globatus there are, at first, only the wart-like rudimentary sucking mouth-parts; but after the last molt the larve acquire ordinary biting mandibles, with which they can gnaw through the skin of their host. However, the food of the ichneumon larve is wholly fluid, their mouth-parts not allowing them to eat the fat-body of their host. .

Other parasitic insects are the larve of the Tachina flies, a group closely allied to the common house-fly. The larve are true maggots, footless, and take their food by suction through the mouth, the mouth- parts being very rudimentary. The Tachina (Senometopia) militaris has been observed by Riley to lay from one to six eggs on the skin of the army-worm, ‘fastening them by an insoluble cement on the upper surface of the two or three first rings of the body.” The young mag- gots in hatching penetrate within the body of the caterpillar, and lying among the internal organs absorb the blood of hs unwilling host, causing it to weaken and die.

Other insectivorous insects are the Aphis-lions, the young of the lace- winged flies Chrysopa and Hemerobius, which are frequently found in trees among plant-lice; also Carabid beetles.

Artificial breeding of parasitic and predaceous insects.— Among the most important preventive measure against the wholesale ravages of insects is the artificial breeding of parasitic insects. We early advocated this in dealing with the Hessian-fly and wheat midge, suggesting the im- portation of the European parasites of the latter species in straw. Dr. Le Baron has experimented with the parasites of the apple bark-louse.

ARTIFICIAL BREEDING OF PARASITES. tT

Professor Kiley in his third and subsequent Missouri reports has shown how easily and practically certain parasites of the Plum Cur- culio and of various scale-insects may be artificially disseminated, and has successfully introduced the most common European parasite (Apan- teles glomeratus) of the imported cahbage worm.*

*The most striking illustration of the good that may be accomplished by this means has, however, been furnished by Professor Riley since these pages were prepared for the printer, and as it refers to an insect very destructive to forest as well as fruit trees, we reproduce here the paper read by him at the Toronto (1889) meeting of the American Association for the Advancement of Science on the artificial importation

-and colonization of parasites and predac eous enemies of injurious insects” :

‘The encouragement of the natural checks to the increase of insects injurious to vegetation may be of a two-fold nature. It frequently happens that an indigenous species is found to have certain parasites in only a portion of the country which it inhabits. In such cases, where it is practicable to transport the parasites, a great deal of good may be accomplished. Cases in point are not uncommon. * * *

But this intentional distribution of the parasites or natural enemies of an injurious insect from one part to another of its native couutry is by no means to be compared in importance with the introduction of such parasites or enemies from one country to another, in which the injurious species has obtained a foothold, without the corres- ponding natural enemies which serve to keep it in check in its original home.

‘The object of the present note is to cite an illustration of artificial introduction on a large scale, which has already been productive of great good. A successful attempt of this kind had been made by me in the case of Microgaster glomeratus, which, after several futile efforts, was introduced from Europe and established in the United States in 1885, and which has now become so widely distributed as to raise the question of its previous existence there. This Microgaster is one of the commonest parasites of the European Cabbage Worm, Pieris rapw, which got a foothold in America, without its European enemies, about the year 1859, and which rapidly spread over the States and parts of Canada, with disastrous results to the cabbage crop.

**The case to which I would particularly allude is, however, far more important and satisfactory. Orange culture has become a very important industry in southern Cali- fornia. The orange groves there have suffered for some years from the attacks of several insects, but particularly of a very pernicious scale insect (Icerya purchasi Maskell). This is one of our largest coccids and, from its habits and characteristics, very difficult to overcome. It does a great deal of damage—not only to the orange and other citrous fruit-trees but to many other cultivated plants and to forest trees. The damage has become so serious during the past few years that many orange- growers have abandoned their groves, while the cost and trouble of protecting these by the use of insecticides have always been great, even where successful. After careful researches I ascertained that the insect was without much question a native of Australia and had been artificially introduced not only into southern California, but also into Cape Colony, in South Africa, and probably into New Zealand; also that in its native home it rarely did serious damage, being kept in check there by-various natural enemies and parasites. Some attempt was made, through correspondence with Mr. Frazer 8. Crawford, of Adelaide, to introduce one of the parasites by mail in 1887. Specimens were received alive and liberated at Los Angeles under confine- ment, but no positive evidence was obtained of multiplication or colonization. Spe- cial effort and introduction on a larger scale seemed necessary.

“Tast autumn and winter in connection with the commission appointed to visit the Melbourne International Exposition and through the State Department I was able to send one of my field agents, Mr. Albert Koebele, to Australia with instructions to study these natural enemies and to send living specimens to California. The principal facts have been recorded in my last annual report as entomologist of the United States Department of Agriculture and in late numbers of ‘Insect Life,” a monthly bulletin

- published under the auspices of the entomologist and his assistants. Without going

into detail I may say that Mr. Koebele’s mission has been eminently successful and that we have succeeded in introducing alive not only the most important of the parasites, an interesting Dipteron (Lestophonus icerye Williston), but also several: predaceous species, and particularly certain ladybirds (Coccinellidz.) These were brought over last winter and spring, have become well acclimated, and are now spreading and multiplying at arapid rate. The latest reports which I have received from California are to the effect that one of the commoner ladybirds but recently described, namely, the Vedalia cardinalis, and another lately described by Dr. D. Sharp as Scymnus res- titutor are multiplying and spreading in a most satisfactory manner. The consign-

5 ENT 2

18 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Coleopterous enemies of borers.—Besides woodpeckers and other birds which pick insects out of bark, and thus do great benefit to forestry, and besides ichneumon and Chalcid parasites of borers, there are many carnivorous grubs which prey upon the borers.

Among the external though less known enemies belonging to the order of beetles, which Perris enumerates from his extended observa- tions on their habits, are a large number which live under the bark of trees. I quote his accounts of them, premising that we have similar insects with like habits in this country; and though the list of scientifie names seems formidable, yet there are no common names for them. I use nearly his own words, with occasional interpolations of English names.

When one of the Scolytids injurious to pines (the Bostrichus stenographus) lays its eggs under the bark, the Platysoma oblongum introduces itself by the hole which has given entrance to the first named insect; it lays its eggsin the gallery of the Bostri- chus, and from those eggs are born the carnivorous larve which devour those of the wood-eating beetles. Other beetles conduct themselves in the same manner in war- ring against other Scolyti. The larve or grubs of Plegaderus discisus destroy the young of Crypturgus pusillus ; another wood-eating beetle, the Aulonium sulcatum, is the deadly enemy of Scolytus destructor, so formidable a foe to shade trees; Aulonium bicolor attacks Bostrichus laricis ; Colydium bicolor preys upon the Bostrichus of the larch; Colydium elongatum ou Platypus cylindrus; Rhizophagus depressus on Blastopha- gus piniperda and B. minor; Laemophleus hypobori on Hypoborus ficus ; Hypophleus pini on Bostrichus stenographus ; and finally Hypophleus linearis on Bostrichus bidens. Who will not be struck by these antagonisms? Who will not admire this infallibility of instinct which causes these insects to discover the tree attacked, and perceive among the species wh ich the tree conceals the victim which has been assigned to them ?

Other beetles exhibit the same sagacity. The larve of several Elaterids (wire- worms) and those of Clerus mutillarius and C. formicarius make war on those of some longicorn beetles of the oak, the elm, alder bush, and the pine. The Opilus mollis and O. domesticus are the enemies of the borers which mine our floors and ceilings; the Cylidrus albofasciatus and the Tillus wnifasciatus prey on Sinoxylon sexdentatum and on Xylopertha sinuata, which seek the diseased branches of the vine and those of several trees; the Tarsostenus univittatus attacks the Lyctus canaliculatus, injuring our timber works; while the Trogosita mauritanica destroys the grain moth.

In an article in the American Naturalist (Xv1, 823) on inquiline wood- borers, or those which usually take up their residence in mines or gal- leries made by true wood-borers, Mr. E. A. Schwarz finds that the com- mon Platypus compositus may itself bore in the thick bark of pine

ments from Australia were received at Los Angeles by Dr. D. W. Coquillet, another of the agents of the division.”-* * *

The people of California are enthusiastic over the grand success of this effort, and the Vedalia is spreading with remarkable rapidity and clearing the trees in its wake. Prof. W. A. Henry, director of the Wisconsin Experiment Station, in a recent report to the Department of Agriculture writes:

‘‘A word in relation to the grand work of the Vepartment in the introduction of this one predaceous insect. Without doubt it is the best stroke ever made by the Agricultural Department at Washington. Doubtless other oftorts have been pro- ductive of greater good, but they were of such character that the people could uot clearly see and appreciate the benefits, so that the Department did not receive the credit it deserved. Here is the finest illustration possible of the value of the Depart- ment to give people aid in time of distress. And the distress was very great indeed.”

INFLUENCE OF TEMPERATURE ON INSECTS. 19

stumps, but in hard wood, as oak, ete., associates with Colydium lineola and Sosylus costatus, living in their mines. Professor Riley has dis- covered that the larva of Hemirhipus fascicularis 1s parasitic on Cyllene picta, living in its mines. Strongyliwm tenuicolle is not a true borer, but Mr. Schwarz has found it in the mines of longicorn borers, wherein it perhaps lays its eggs.

Influence of temperature on insect life-—The following statements are taken from Judeich and Nitsche’s Lehrbuch, and will apply to insects in this country:

“The influence of temperature may either work injuriously on insect life from extremes of heat or cold, or from sudden and, at given times of the year, abnormal changes. High temperature does not directly in our climate, in the natural course of nature, affect insects. On the other hand, it is not unfrequently the case that insects, suddenly overcome by the frost, freeze to death in great numbers, since with the lowering of the temperature, benumbed by the cold, they can not reach crevices or holes out of the reach of the frost. As an example, we may refer to the winter of 1864~’65, in which, in the district of Mark and the prov- ince of Saxony, the caterpillars of pine silk worms and measuring worms 1lemained unusually long on the trees, and the former froze in the mid- dle of December,—12.5° C., and the latter during the considerably greater cold in January. Hence the influence of even very great cold on the normal hybernating stages of our insects is not very great. In the summer of 1854 the ‘nun’ moth had very generally laid its eggs in eastern Prussia uncovered on the bark, and these did not freeze in the hard winter of 1854~’55, notwithstanding the expectation that they would, based on a temperature of 30 to 35° C.

According to the observations of Regener, openly exposed caterpil- lars of the pine silk worm endured —12.5° C. The other stages froze earlier, the pupa at —6° C., the moth at —7.5° C., the eggs at —10° C. According to Duclaux (Comptes Rendus, 83, p. 1079) the eggs of the silk worm endure well remaining two months in a temperature of —8° C,

“Great fluctuations of temperature during the winter produce an abnormal interruption of the winter’s rest or hibernation, and thus cause the death of many insects.”

Generations or broods.—The length of time which any insect needs in order to complete a single developmental cycle from the time the egg is laid until the insect is mature and fit for reproduction is a genera- tion; a generation then is the time from anegg to anegg. The length of time of a generation varies, of course, in different insects. Gener- ally an insect requires twelve months for its development. In such a case we speak of an annual generation. On the other hand an insect which requires for its developmental cycle twenty-four, thirty-six, or forty-eight months has a biennial, triennial, or quadrennial generation. The European May beetle has, in northern Germany, a quadrennial gen- eration; the seventeen-year locust has a generation of seventeen years.

On the other hand, there are insects which repeat their developmental

20 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

cycle two, three, or more times in a year; such insects are said to be double or treble-brooded. Lophyrus abietis and other species are double- brooded, while many butterflies are double or treble brooded, and the Aphides have from nine to fourteen generations in a season, 7. é., from spring to autumn. In all cases of seasonal dimorphism or of partheno- genesis there are several generations.

Judeich and Nitsche graphically represent as follows the generations of the European Lophyrus pini, with its double generations, which will also apply to our L. abietis: The egg is denoted by a point (. ), the larva by a dash (—), the larva lying in a semi-pupa condition in the cocoon, thus (@); the pupa by the following mark ( @ ), and the imago by a cross (+); the time during which the larva is eating, by a heavy dash (MMH); lastly, the period of injury by the larva is placed under, the time of imaginal injury above, the mark for the stage under consid- eration.

| Jan. | Feb. | Mar.| Apr. | May.| June.| July. | Aug. |Sept.| Oct. | Nov. | Dec.

++ |-——|———\ee+|+ 1860. | | eae -|.——|--—| eeleasioss | BEE SeE 1881. O29'S5e Ssce@|e++

ya ne

In the United States a butterfly or moth which is single-biooded in the New England or northern Central States may be three-brooded in the Southern or Gulf States. A generation or brood which appears and ends in the summer is shorter than that which hibernates.

Thus the summer generation of the species of pine saw-flies (Lophyrus) is about four months, the winter generation about eight months. Hence the length of the generation depends on the temperature and climate, as does also the number of broods or generations. ‘This influ- ence of climate is, as is well known, so considerable that a species of insect which has a double generation in a certain locality, in another place with a colder climate is only single-brooded, while in a warmer climate it is three-brooded. An example is Hylesinus piniperda. Thus also a species of insect whose generations in a certain middle location is, for example, four-yearly, in a more southern situation is three-yearly. A proof of this is afforded by the May beetle, which north of the main line’ is four, but south of it needs only three years to complete its development. A certain species of insect may moreover in the same locality in a warmer and more favorable year be double-brooded, while in the next harsher unfavorable year it is single-brooded. But if the checking influence of the harsh weather is less, then even iu an un- favorable year a second generation may begin to develop, but does not complete its cycle by the end of twelve months. Hence there are in twenty-four months three generations, and then arises what Ratzeburg calls a ‘one-and-a-halfgeneration.’ Of this Tomicus bidentatus not rarely affords an example.

GENERATIONS OR BROODS

OF INSECTS. 21

‘«We have observed that certain species of insects and often individ- ual insects may without any assignable reason remain a considerably longer time than usual in the pupa state. Lyda stellata usually has a single brood (one year generation) while it frequently happens that from the pupa beginning the first of May, the image does not fly at the end of May or in June, as is the rule, but that the pupa state lasts over to the next May, when the adult flies. The pupal rest in this case lasts, instead of three weeks, more than a year. A similar case is that of Cnethocampa pinivora. This relation is connected with the fact that insects are cold-blooded, or better, poikilothermie, 7. e., changeably warm animals. We understand thereby such animals as those whose peculiar body heat, although constantly a little higher than that of the surround- ing medium, the air, water or earth, i. ¢., their habitat, yet varies with the changing temperature of this medium. In contrast with these are the warm-blooded, or, more exactly, the homeothermal, i. e., animals with an even temperature which as long as they live steadily maintain their own normal temperature up to a height ranging at most 19°C. The blood-heat of a healthy man, although he may be exposed to a degree of cold of 30° C. or a warmth of + 30° C., remains steadily at 38° C. (Judeich and Nitsche.)*

The duration of development of a warm-blooded animal is definite. The development of an insect’s eggs, however, is analogous to that of a ftish. We best see this when at the beginning of spring the leafing out of the foliage is late and the caterpillars of Clisioeampa hatch cor- respondingly late. Exact series of observations of indubitable cer- tainty are scarcely at hand, but, add our authors,t we will cite the posi- tive statements of Regener{ on the influence of temperature on the duration of development and of life of the pine Bombyx at different temperatures, though, indeed, they are somewhat inexact and incom- plete.

Provisional tabular view of the life-history of the Pine spinner (Gastropacha pini) at dif- ferent temperatures, after Regener.

Duration (in days) of— Temperature, | Caterpillar, (6; Egg-stage, | from hatch- aah : Prepara- | | from laying | ing to spin- Sens ms ; tions for | Pupal rest. | | to hatching. ning of 5 pupa. | cocoon. =] RSCG es | meee ns comet Per cok Gaeta all eee. Se ees, i scects d So ocd Getall pees ieee oe SIO gain i ES are Sb ae BOOT Wie eeianen sets als Se Pay Seas ted es oad | |} + to 11° 36 LOG lates ce ose es| sean c aces coos Sec cte tess toas + 11° to 14° 26 DOS GP ese ias ok oe LET us leeiseeics cc kee | + 15° to 19° 20 119 3 9 49 | + 18° to 21° 18 84 24 5d 36 | -+ 20° to 24° 17 67 2 24 26 + 24° to 28° 16 56 4 2 21 |

*Each degree of the Centigrade thermometer is equal to 14° of Fahrenheit; and is at the freezing point of water. tJudeich and Nitsche, I, 116.

tE.

Regener.

weise, Lebensdauer und Vertilgung der grossen Kiefernraupe. Baensch’s Verlag, 1865.

Leipzig:

Erfahrungen iiber den Nahrungsverbrauch und iiber die Lebens-

Emil

22 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

What combination of different climatic influences in reality causes that one and the same insect eitherin different years in the same locality, or in different localities in the same year, needs a time different in length for the completion of a generation, could not be determined in advance. Ratzeburg was inclined in this matter to follow the similar relations established by Boussingault as regards the duration of vege- tation of plants. According to the views of this French observer each plant needs a definite amount of heat; @. ¢., the sum of the mean daily temperature of its time of vegetation should be a constant one, while the duration of the time of vegetation may itself vary. It is also theo- retically assumed that a plant needs heat amounting to 2000° C., so that it can develop in one hundred days, with an average mean tempera- ture of 20° C.; also as well in one hundred and eleven with 18° C., and in ninety-one days with an average mean temperature of 22° C.

Ratzeburg* applies this to the case of the May beetle. He says:

Interesting and important is, moreover, the behavior of the May beetle. In mid- dle and northern Germany its generation is a quadrennial one, in southern Germany a triennial one. The reason of this plainly lies in the climatic features of those regions. In the south the season opens much earlier and closes later, which must exert some influence on animals of a pliable nature, such as the May beetle, as well as on plants. The grub there has, in three years, a start of at least three months, in comparison with those in the north; also, even in the third summer, its develop- ment may be ready, though we should consider that with us in the fourth summer, it is usually in July; it eats no more, and in August pupates. Erichson found that the ‘pupation sometimes occurs even in May ; it fails only a little of a three-years’ genera- tion. Finally, everything depends, as in plants, on the amount of heat in the soil and air which a genus or species needs for its development. If the May beetle does not find this in the third summer, it requires it in the fourth, and can shorten the time in an especially favorable year, but with us can never complete it in three years.

Shouid we, for example, add together the mean temperature of Berlin for twelve months it would amount to 106° C., and for four years 4x 106°=424°; on the other hand Carlsruhe would in three years give 375°, and beyond the Alps there is fully 424°. Should we also take into account the temperature of the soil, the amount in the south would be still better for the May beetle. In north Germany in humous sandy soil (in the Waldschutten), the thermometer in the hybernation stage of the May beetle in one month, from the end of March to the end of April and beginning of May, rises from +6° to +-9° C. How is it now in the south? All other insects which inhabit both the north and south must have a ‘‘ heat surplus;” but since this lasts only one, but at the most two years, it follows that such results as in the case of the May beetle, which requires so long a time to develop, can not occur there.

Accurate researches on this problem are still very rare. Herr Uhlig in Tharand found by observations on the temperature made three times daily during a generation of Tomicus typographus, from May 30 to July 21, a heat-amount of 145° C., or divided, a daily amount of 22.029; dur- ing the second generation, from August 4 to October 3, an amount of 1228.59, or divided, a daily amount of 20.48° (Thar. Tagebuch, 25 Bd., s. 256).

Ratzeburg’s statement should also be noticed. A double brood of Tomicus typographus appears if, as is usual in central Germany, the

*Die Waldverderber und ihre Feinde; 8°, p. 360.

ne ee EF

HIBERNATION STAGE. 23

mean temperature of the months reaches 13° C.in May, 17° C. in June, 19° C. in July, 17° C. in August, and 14° C. in September.

But it has now long been proved that plant physiology does not accept the simple heat-amount of Boussingauit, and we have besides to consider the period of sunlight (duration of light) during which alone the chlorophylH-containing parts are assimilated, as well as the mean temperature reached in the sun—at best measured by an actinometer. However, in animals the transformation of tissue depends much less on the amount of light than in plants, hence simply the total heat- amount can searcely be sufficient to explain the differences in the ani- mal developmental processes, especially if we only take into account the temperature of the air. It would be much better to take into con- sideration the temperature of the soil throughout their larval life of insects living in the earth, and in insects living in wood the temperature of the tree, 7. e., the portion of the tree concerned. Compare the exact researches of Krutzsoh.* Such researches should determine what is the minimum temperature at which generally an advance in development would be possible. Also the optimum temperature, 7. e., the tempera- ture which is most favorable to any process should be noted.

For example, these optima would require to be difierent for the dif- ferent developmental stages in the insects, as would the temperature- minima supportable to the same. We also know, through the re- searches of Semper, t that as in the germination, growth, and flowering of plants, so also in animals; 7. e., in our common fresh water snails, the temperature-optima for the different function, 7. e., forthe ripening of the sexual products and for growth, are different, a thesis which by Semper has been applied to a striking attempt at an explanation of the occurrence of wingless, larval-like, but still sexually developed Ortho- ptera in southern lands, 7. ¢., the so-called ‘stick insect” (Judeich and Nitsche).

Hibernation stage.—The developmental cycle of two species of insects with similar generations may, under similar climatic relations, produce a very different shape, namely, in the cases where they pass the winter in different stages of development, since the hibernation-stage is always the longest, and hibernation is possible in the egg, as in the larva, pupa, or imago, stage. But under normal relations a given species of insect always hibernates in the same stage, 7. e., many moths as pupze, some butterflies as imagines.

It is not possible, then, to predicate in general for a single order of in- sects as to what stage they may hibernate in, since species of the same family differ in this respect. Thus, for example, according to an estimate

*Untersuchungen iiber die Temperatur der Baume im Vergleiche zur Luft und Boden-Temperatur. Forstwirthschaftliches Jahrbuch der Akademie Tharand, x,

_ 1854, 214-270.

tAnimal life as affected by the natural conditions of existence. The International Scientific Series. New York, 1881.

24 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. .

of Werneburg’s* of the German Macrolepidoptera 3.4 per cent. hiber- nated as egg, 66.9 per cent. as larve, 28.2 per cent. as pupa, and 1.5 per cent. as imagines, while in considering a single family the result stood entirely different. Thus all the Zygenide hibernated as larve, most Sphingidz as pupe, and of the butterflies 9 per cent. in the egg, 54 per cent. in the larval, 28 per cent. in the pupal, and 9 per cent. in the imaginal state. Thus it appears that insects which, not to take too narrow a limitation of genera, belong to one and the same genus, may hibernate in wholly different stages.

Of many species of insects only the females hibernate after impreg- nation in autumn, ¢@. é., many gnats and our common paper wasp (Vespa), while the honey bees tolerate no drones in their hives, so that only the queen with the workers lives through the winter.

But abnormal meteorological phenomena may so effect such changes that a species of insect may hibernate in a different stage of develop- ment from what is customary. Indeed there are cases where an insect may, though rarely, live through the winter in another of the four stages of metamorphosis than the usual one, for it has been observed that the pine Gastropacha lives through the second winter as pupa. (Ratzeburg: Die Forstinsekten, ii., 147, Anm.) On the other hand, it is very common for caterpillars, which seek winter quarters when half erown. This they have to do as very young animals. Thus the pine Gastropacha hibernates after the first molt, instead of, as usual, after the second.

Insects which have generations requiring several years must natur- ally hibernate several times. This may occur in the same or in different stages of metamorphosis; thus, for example, the one, two to three years’ generation of the May fly remains as a larva in the water, while the May beetle passes three winters as a larva, but the fourth as an imago.t

For the following interesting remarks we are indebted to Judeich and Nitsche’s work on Forest Entomology :

Diseases of trees produced by the attacks of insects.—Various deformi- ties and alterations of the wood, branches, and leaves result from the attacks of borers and bud and leaf devourers. Before the tree com- pletely heals there is a more or less long period during which the tree assumes an abnormal, morbid appearance. Such appearances in which the disease affects the growth of the wood are: 1. The appearance of unusual new structures, such as leaves, ete., both in form and dimensions. 2. The origin of repaired parts from representative growths or sleeping buds. 3. The diminution of growth.

The appearance of unusual new growths.—In general the changed sickly new growths are smaller and more sparse than the normal. A thinner foliage in the year after the damage is generally the result of

*A,. Werneburg. Der Schmetterling und sein Leben. 8°. Berlin: 1854. +The foregoing remarks on insect-generations and hibernation have been trans- lated from Judeich and Nitsche’s valuable work on Central European Entomology.

DISEASES OF TREES PRODUCED BY INSECTS. 25

stripping the trees bare. After injury by the nun caterpillar the trees seem to suffer most in the second year following the damage.

The new growth of the fir generally sends out only very short needles, which remain as brush shoots (Fig. 3.) In the pine there arises after defoliation from lateral buds ‘‘ rosette shoots,” 7. e., very short, persist- ing growths bearing dense, short, broad, and serrate (gesaigte) single needles (Fig. 4). But on the other hand cases occur, when many buds are destroyed, where the remaining remnant of the entire sap-stream is used and the organs formed out of it, 7. e., needles or leaves become unusually large, as for example in the ordinary pine, in which case the leaves bear three needles.

Fig. 3. Lateral twig of a fir eaten by nun cater- Fig. 4. Rosette shoot on the pine. After pillars in 1856, which in 1858 only produced Ratzeburg. ‘‘brush needles.” After Ratzeburg.

Similar relations are observed in the helve oak attacked by Orchestes. Generally the first growth seems to grow straight on and resist the in- jury arising from the laying of the eggs by the female of this leaping weevil, and the injured leaves are crumpled, but such leaves on the Johannis growth (Johannistriebe) become unusually large and abnor- mally formed, while those situated on the summit entirely assume their normal shape.

The origin of repaired parts from representative indefinite growths is very general.—The clearest example is afforded by pines deprived by Retinia buoliana of their terminal shoots. In this case there grows out after a certain time a shoot of the uppermost branch (Quirles), which now becomes the terminal shoot, though in growing up there is a crum- bling of the stem in the place under consideration.

For the formation of mostly abnormally shaped organs which have been replaced from sleeping buds, the pine affords the best example. From the usually dormant sheathing-buds on the point of origin of the

_ short shoot occurring between every two pine needles, are developed

26 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

(in the course of the appearance of needles, and dwarfing the leading shoot) sheathing shoots, which, however, usually reach no great age, but are provisionally of much importance to the life of the tree.

The loss of increase in size resulting from disease is twofold. Some- times the shoots suffer in decrease in length, at others in shrinking in size. The diminution of length is shown after the year succeeding that in which the injury took place; that in the terminal shoot of the branch, and especially the topmost shoot, the needles remain shorter. Not until later do they again assume their normal length. The fir also, whose topmost shoot is here repre- sented (Fig. 5), after injury received in the year 1857 formed only short leading shoots, but in 1861 again formed a strong shoot.

The diminution of the growth in diameter is especially noticeable in the loss of the foliage or needles, which sometimes occurs in the year of injury, but more decidedly the following year.

After a greater loss of leaves the annual rings

eet Saeaulseere ea

eeisianwie S32 (So Stic Fig. 6. The last seven rings of pine stem almost wholly defoliated in 1858, but not killed outright. After Ratzeburg.

Fig. 5. Terminal shoot of a 4 b fir defoliated by thenun-cat- are Smaller and feebler, and this may sometimes

Ses tea: Ge ee last over for many years. (Fig. 6.) year's growth. After Ratze- Nordlinger has repeatedly found signs of de- Bune, foliation by the May beetle for three years on oaks, also on Carya alba, in southern Germany, indicated by very small annual rings.

The counting of the annual rings to ascertain the age of the tree in the practically so important matter of discovering its rate of growth is rendered unsafe by the formation of double rings, which may result from the sudden leaving-out in summer on young shoots, or by the co- alescence of two annual rings in one, and sometimes even by the total omission of aring. The sharply-defined difference between the spring and autumn growth of wood as denoted by the color, ‘‘ white and brown wood” of an annual ring, especially in the coniferous woods, enable them to be very easily counted, provided there is no interruption in the growth. In the deciduous trees the two layers of the annual rings are

———

REMEDIES AGAINST FOREST INSECTS. 27

less sharply distinguished ; and it is only in the oaks, ashes, and elms, where the pores are arranged in rings (“ringporen”) that the richly vascular spring wood sharply defines each new annual ring from the denser and more compact autumnal layer of the preceding ring.

Injuries in the production of the resin also arise from molds, which effect a transformation of the starch and of the cellulose into turpen- tine, and thus cause a morbid increase as well as outflow of the resin or

‘pitch; e.g., Agaricus melleus, Aecidium pini, Peziza Willkommii. A]l in- sects which externally gnaw the bark or the wood of coniferous trees, e. g., bark borers, wood wasps, Grapholitha pactolana and G. coniferana, Dioryc- tria abietella ; different weevils (Hylobius and Pissodes), produce a more or less strong flow of pitch or resin. But also in the interior of the wood arise abnormal formations, as, for example, the so-called pitch-chains. We understand by these a morbid increase of the pitch canals of coni- fers into concentric chains which often coalesce; also the pitch canals in the last year’s ring are completely omitted.

Prevention and remedies against forest insects—Besides the insecticides for such insects as feed upon the leaves, and the means of applying them to single trees, to groves, or to more or less extensive forest areas, and which will be described farther on by Professor Riley, there are some suggestions which may be made as to the remedies against borers.

In the first place it should be borne in mind that dead stumps and decaying trees or logs left standing near groves or road-side trees, are a continual menace to healthy trees, since they afford an asylum or breeding-place to timber and bark borers. Such objects, large and small, should be cut down or pulled up and burnt. Forests should be kept free from standing dead trees and stumps, or if left standing should have the bark removed. It is well known that lumberers remove the bark of logs to prevent injury to the lumber of sawyers,” or the grubs of timber-beetles.

While in the virgin spruce forest on the eastern shores of Lake Ken- nebago, Maine, which had never been lumbered, my attention was forcibly called to the necessity of cutting down the dead and dying spruces soas tosave the healthy trees. It is of course out of the question to burn such dead timber, but we question whether it would not in the long run pay the owners of lumber lands to send parties in to cut down the trees, remove the bark, and thus prevent the breeding of bark- borers, and hasten the decay of trees infested by timber and bark-borers.

Plantations and forests of limited extent can with comparative ease and slight expense be kept in neat, trim order by judicious thinning and removal of injured or infected branches, the latter being burnt.

Borers in shade and ornamental trees.—Our experience in detecting the gashes in the bark of the spruce and fir made by the female Monoham- mus, the parent-beetle of the “sawyer” or borer, and those made in Trock-maples by the female beetle of the maple-tree borer, so destructive in parks and streets, has taught us that it is quite practicable during

28 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

August to find these gashes and to cut out the small grubs in the bark underneath, at a time when they have not descended deep into the tree. An observant and intelligent gardener could easily prevent further damage from such a cause.

One of the most formidable and deadly borers of the oak, from Maine to California and Texas, is the caterpillar of the Carpenter moth. In Europe a similar borer is dealt with in the following ways, according to different writers quoted by Miss Ormerod in her Manual of Injurious Insects.” A wire thrust into the ‘‘mine” or hole may destroy them. Paraffine injected by a sharp-nozzled syringe with as much force as pos- sible into the holes where the caterpillars are working is a good remedy, also any oily or soapy mixture (kerosene injections might injure the tree more than the borer). The flames of sulphur blown into the hole might be of use. ‘‘ Where a tree is much infested, it is the best plan to cut it down, split it, and destroy the caterpillars within. As many as sixty or more caterpillars may be taken from one tree, and when in this state it will never thoroughly recover, and it becomes a center to attract. further attack, as well as one to spread infection.”

As preventive measures, to prevent oviposition, the lower part of the trunk should be washed with whale-oil soap of the consistency of thick paint.. This should be done at or about the time the moth lays her eggs, viz, as early as April and May in Texas, and in June and July in the Northern States.

These suggestions will also apply to the Sesian borers of the maple, ash, ete.

Prevention and remedies against Timber-beetles and Bark-borers.—The family of bark-borers (Scolytide) include those which live in the bark and those which descend into the wood, the latter often being called timber-seetles. We have given in this work some of the known facts regarding their habits, which are very curious. Hichhoft’s excellent. work in German on European bark-beetles is replete with fresh obser- vations on these beetles. We may here draw attention to what Hich- hoff says concerning some causes of the undue increase of these insects, and their sudden appearance in places not before frequented by them.

The chief factors in the growth of bark-beetles are good weather and sufficient nourishment. An uninterrupted dry, and hence hot, summer. checks the growth of the larva, and retards the speedy development and more often prevents a repetition of another brood, than an unin- terrupted wet and cold spring and summer. Hence, on account of great heat and drought many trees survive which would otherwise be injured by the later brood of bark-beetles. The most favorable conditions for the increase of bark-beetles are doubtless a warm early spring and a warm summer, with frequent rains and a long, mild autumn.

Other circumstances, says Eichhoff, favorable to the increase of bark- beetles, are strong winds, snow, frosts, forest fires, the devastation wrought by caterpillars, whereby the trees are more or less decorti-

REMEDIES AGAINST BARK-BEETHLES. 29

cated in places and otherwise wounded, so that the beetles can gnaw into the wood or inner bark, lay their eggs, and thus finally form brood- galleries.

Hichhoff asks the pertinent question: ‘‘ How do great numbers of bark-beetles pass into regions where perhaps before they were scarcely known by name? For example, at the end of a period of fifty years, all at once Tomicus curvidens appeared in the Botanic Garden of the _University of Vienna, and were very destructive to different exotic cedars, larches, etc., afterwards attacking white firs, which contained numbers of tbe beetles.

The bark-borers, especially Tomicus typographus, belong to those in- sects which sometimes produce extensive devastations by immigration from without. According to a German writer they doubtless migrate for short distances, since not seldom there result local destruction of groups of firs when previously no bark-borers were to be seen. It is also certain that forests previously entirely free from bark-beetles be- come infested by bark-beetles bred in wood and lumber yards. It is difficult and questionable how far such an immigration may extend. An example of an extensive emigration of Tomicus typographus is afforded by H. Tiedemann in the province of Nishny- Novgorod.

In the midst of an imperial forest of about 2,500 ha lying in the district Arsamass, and composed almost exclusively of hard-wood trees, occur two fir-growths of 56, perhaps 60, ha in extent. In both there was no windfalls, no burnt areas, but a good close growth in which no bark-borers had appeared. Suddenly in the year 1883 the bark-borers were so numerous that 2,000 fir trunks at once fell, and had to have the bark stripped off and burnt. The appearance of the bark-beetles is in this case only to be explained by their flying into this area. The nearest fir-growths are from 15 to 20 kilometers distant, and those of sufficient size to afford time for the infection of the fir-growths in question, about 50 kilometers distant.

Perhaps the best method 0 preventing or stopping the work of bark- beetles is that of a Frenchman, M. Robert, given in the Gardener’s Chronicle and quoted by Miss Ormerod:

The best remedy appears to be that adopted with great success in France by M. Robert, after careful observation of the circumstances which stopped the operations of the female beetle when gnawing her gallery for egg-laying, or which disagreed with or destroyed the maggots, and is based in part on similar observations of the effect of flow of sap to those noticed in England by Dr. Chapman.

It appeared on examination that the grubs died if they were not well protected from the drying action of the air; on the other hand, if there was a very large amount of sap in the vegetable tissues that they fed on, this also killed them; and it was observed that when the female was boring through the bark, if a flow of sap took place she abandoned the spot and went elsewhere. It was also noticed that the attack (that is, the boring of the galleries which separates much of the bark from the wood) is usually under thick old bark, such as that of old elm trunks rather than under the thinner bark of the branches. Working on these observations, M. Robert had strips of about two inches wide cut out of the bark from the large boughs down the trunk to the ground, and it was found that where the young bark pressed forward to heal the wound and a vigorous flow of sap took place that many of the maggots near if were killed, the bark which had not been entirely undermined was consolidated, and the health of the tree was improved.

30 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Working on from this, M. Robert tried the more extended treatment of paring off the outer bark, a practice much used in Normandy and sometimes in England for re- storing vigor of growth to bark-bound apple trees, and noted by Andrew Knight as giving a great stimulus to vegetation. M. Robert had the whole of the rough outer bark removed from the elm (this may be done conveniently by a scraping-knife shaped like a spoke-shave). This operation caused a great flow of sap in the inner lining of the bark (the liber), and the grubs of the Scolytus beetle were found in almost all cases to perish shortly after. Whether this occurred from the altered sap disagreeing with them, or from the greater amount of moisture around them, or from the maggots being more exposed to atmospheric changes, or any other cause, Was not ascertained, but the trees that were experimented on were cleared of the mag- gots. The treatment was applied on a large scale, and the barked trees were found, after examination by the Commissioners of the Institute at two different periods, to be in more vigorous health than the neighboring ones of which the bark was un- touched. More than two thousand elms were thus treated.

This account is abridged from the leading article in the ‘‘Gardener’s Chronicle and Agricultural Gazette,” for April 29, 1848, and the method is well worth trying in our public and private parks. It is not expensive; the principle on which it acts as re- gards vegetable growth is a well-k nown one, and as regards insect health it is also well known that a sudden flow of the sap that they feed on, or a sudden increase of moisture around them, is very productive of unhealthiness or of fata] diarrhea to. vegetable feeding grubs.

A somewhat similar process was tried by the Botanic Society, in 1842, on trees in- fested by the Scolytus destructor in the belt of elms encircling their garden in the Re- gents’ Park, London. ‘‘It consists in divesting the tree of its rough outer bark, be- ing careful at the infested parts to go deep enough to destroy the young larve, and dressing with the usual mixture of lime and cow-dung.” This operation was found very successful, and details with illustrations were given in a paper read in 1843 be- fore the Botanic Society.

Various applications have been recommended, such as brushing the bark of infested trees with coal-tar or with whitewash, in order to keep off the beetle attack. Any- thing of this kind that would make the surface unpleasant to the beetle would cer- tainly be of use so long as it was not of a nature to hurt the tree, and if previously the very rugged bark was partially smoothed it would make the application of what- ever mixture might be chosen easier and more thorough.

Anything that would catch the beetles, either going into or out from the bark, like coal-tar, would be particularly useful, and probably strong-smelling and greasy mixt- ures, such as fish-oil soft soap, would do much good.

Washing down the trunks of attacked trees has not been suggested, but, looking at the dislike of the female beetle to moisture in her burrow, it would be worth while, in the case of single trees which it was an object to preserve, to drench the bark daily from a garden-engine for a short time when the beetles were seen (or known by the wood-dust thrown out) to be at work forming burrows for egg-laying.

The possibility of carrying out the important point of clearing away or treating

infested standing trees depends, of course, on local circumstances; but, whatever

care is exercised in other ways, it is very unlikely that much good will be done in lessening attack so long as the inexcusable practice continues of leaving the felled

trunks of infested elms lying, with their bark still on, when containing myriads of

these maggots, which are all getting ready shortly to change to perfect beetles, and to fly to the nearest growing elms.

Such neglected trunks may be seen in our parks and rural wood-yards all over the country, where, without difficulty, the hand may be run under the bark so as to detach feet and yards in length from the trunk all swarming with white Scolytus. maggots in their narrow galleries.

This bark, with its contents, ought never to be permitted to remain. Where it is loose it may be cleared of many of the maggots by stripping it off and letting the

es

REMEDIES AGAINST FOREST INSECTS. ol

poultry have access to it; or, if still partly adhering, it may be ripped from the wood by barking tools and burnt; but it is a tangible and serious cause of injury, and if our landed proprietors were fully aware of the mischief thus caused to their own trees and those of the neighborhood they would quickly get rid of it.

INSECTICIDES AND MEANS OF APPLYING THEM TO SHADE AND FOREST TREES.*

This subject may be divided into two parts, viz, (1) a discussion of insecticides and (2) a discussion of insecticide apparatus.

(1) INSECTICIDES.—Remedial measures against forest-tree insects are not different from those employed against the insect enemies of fruit- trees or farm and garden crops. The same species are frequently the culprits in both cases; and, in general, insects of the same orders and families, having similar habits and requiring similar treatment, attack wild-growing, woody plants and the cultivated sorts.

For convenience of treatment, the first part may be considered under the following heads: Insecticides which act through the food; insecti- cides which act by contact; fumigants and gases,

INSECTICIDES WHICH ACT THROUGH THE FOOD.—These insecticides are available against all mandibulate insects that feed externally on the leaves, such as the larve of Lepidoptera, larve and adults of leaf: feeding beetles, and saw-fly larve. Gall-insects, leaf-miners, and in- sects which burrow beneath the bark or in the wood cannot be con- trolled by these means.

It would be possible to enumerate under this heading a large number of substances depending for their effects on arsenic, strychnine, or other poisons, but I prefer to limit the discussion to the consideration of two substances which are now commonly used to the exclusion of nearly all others.

Paris green and London purple.—The arsenites of copper and eal- cium, Paris green and London purple, are so well known as not to need particular description here. The safety and efficiency with which they can be used and their slight cost fully satisfy all the demands of practical work.

As containing records of a general nature, together with full in- structions for the use of these poisons, [ can not do better than quote -from Bulletin No. 10 of the division of entomology,t the conclusions being based on experiments under my direction, especially by the late Dr. W.S. Barnard.

The quotation refers particularly to work against the imported Elm leaf-beetle (Galeruca xanthomelena) and deals with the treatment of elm trees only, but the results obtained may apply to other insects infesting various shade and forest trees. The recommendation given

*Prepared, at the author’s request, by Professor Riley.

tOur Shade Trees and Their Insect Defoliators, by C. V. Riley, Entcomologist, Washington, 1887. Second revised edition, 1888.

32 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION

will need to be modified to correspond with the varying conditions in habits and life-history of any particular species, as found detailed in the following pages of Dr. Packard’s report:

Effects of Arsenical Poisons on Insect and Plant.—Species of elms are somewhat differently affected by the poison. When treated alike there is always manifest some differeuee in the susceptibility of different elms to the corrosive effects of the poison. Even individuals of the same species or variety are differently impaired. Asa rule, those which suit the insect best are injured most by the poison, and those which resist the insect most withstand the poison best. The latter have coarser foliage with a darker green color and more vigorous general growth; the former have more delicate foliage, lighter in color and weight, apparently less succulent.

Certain elms of the species U. campestris and other species which were over- poisoned, and shed most of their leaves in consequence in the last of June, 1883, sent out a profuse new growth of leaves and twigs. The foliage fell gradually for three weeks, and this was somewhat promoted by the succeeding rains.

The larve move from place to place so seldom that, if the leaves are imperfectly poisoned from the mixture being weakly diluted or from its application only in large, scattered drops, which are much avoided by the larve, they are not killed off thor- oughly for several days, and in all cases it requires considerable time to attain the full etfect of the poison. This result appears on the plant and on the insect. After each rain the poison takes a new effect upon the plant and the pest, which indicates that the poison is absorbed more or is more active when wet, and that it acts by de- hydrating thereafter. Where the tree is too strongly poisoned, each rain causes a new lot of leaves to become discolored by the poison or to fall. On some of the trees the discoloration appears in brown, dead blotches on the foliage, chiefly about the gnawed places and margins, while in other instances many of the leaves turn yellow, and others fall without change of color. The latter may not all drop from the effects of poison, but the coloration referred to is without doubt generally from the caustic action. The poison not only produces the local effects from contact action on the parts touched by it, but following this there appears a more general effect, manifest in that all the foliage appears to lose, to some extent, its freshness and vitality. This secondary influence is probably from poisoning of the sap in a moderate degree. When this is once observable, no leaf-eater thrives upon the foliage. Slight over- poisoning seems to have a tonic or invigorating effect on the tree.

Preventive Effects of the Poison.—In this grove the elms that were poisoned in 1882 were attacked in the spring of 1883 less severely than were those which were not poisoned the previous year. This would seem to imply that the insects deposit mostly on the trees nearest to where they develop, and are only partiaJly migratory before ovipositing. The attack afterward became increased, probably by immigration and the new generation, so that later in the season the trees were mostly infested to the usual extent.

In the region of Washington a preventive application of poison should be made before the last of May or first of June, when the eggs are being deposited and before they hatch. This will prevent the worms from ever getting a start. By the preventive method the tree escapes two kinds of injury: first, that directly from the eating by the in- sect ; second, that which follows indirectly from the deleterious effects of the poison on the plant, for its caustic effect is much greater where the leaves have been so gnawed that the poison comes in contact with the sap.

Treatment with London Purple.—Already early in June the insect appears plentiful. On June 7, 1882, it was at work on all the trees, and its clusters of eggs were numer- ous beneath the leaves. Some of the trees had half ofthe leaves considerably gnawed and perforated by larve of all sizes, and by the adults. At this date fifteen trees, constituting the south part of the grove, were treated.

Preparation of the Poison.—London purple (one-half pound), flour (3 quarts), and water (barrel, 40 gallons) were mixed as follows: A large galvanized iron funnel of

a i te ee

REMEDIES AGAINST FOREST INSECTS. 33

thirteen quarts capacity, and having a cross-septum of fine wire gauze, such as is used for sieves, also having vertical sides, and a rim to keep it from rocking on the barrel, was used. About three quarts of cheap flour were placed in the funnel and washed through the wire gauze by water poured in. The flour in passing through is finely divided, and will diffuse in the water without appearing inlumps. The flour is a suit- able medium to make the poison adhesive. The London purple is then placed upon the gauze and washed in by the remainder of the water until the barrel is filled. In other tests the flour was mixed dry with the poison powder, and both were afterward washed through together with good results. It is thought that by mixing in this way less flour willsuffice. Three-eighths ofa pound of London purple to one barrel of water maybe taken as asuitable percentage. Three-eighths of an ounce may be used as an equivalent in one bucketful of water. The amount of this poison was reduced to one-fourth of a pound to the barrel with good effect, but this seems to be the min- imum quantity, and to be of value it must be applied in favorable weather and with unusual thoroughness. With one-half or three-fourths of a pound to the barrel, about the maximum strength allowable is attained, and this should be applied only as an extremely fine mist, without drenching the foliage.

Effects of the Mixture.—The flour seems to keep the poison from taking effect on the leaf, preventing to some extent the corrosive injury which otherwise obtains when the poison is coarsely sprinkled or too strong. It also renders the poison more per- manent. On the leaves, especially on the under surfaces, the London purple and flour can be seen for several weeks after it has been applied, and the insect is not only destroyed, but is prevented from reappearing, at least for a long period. By poisoning again, a few weeks later, the insect is deterred with greater certainty for the entire season. By being careful to administer the poison before the insect has worked, and, above all, to diffuse the spray finely, but not in large drops, no harm worth mentioning will accrue to the plant from the proportion of poison recom- mended. The new growth, that developed after the first poisoning, was protected by one-fourth of a pound to the barrel in 1882. From midsummer until autumn the unpoisoned half of the grove remained denuded of foliage, while the poisoned half retained its verdure. The little damage then appearing in the protected part was mostly done before the first treatment. Eggs were laid abundantly throughout the season. Many of these seemed unhealthy and failed to develop, probably because they were poisoned. Many hatched, but the young larve soon died. The eggs were seldom deposited on the young leaves that were appearing after the poison was ap- plied, but were attached to the developed leaves, and here the larve generally got the poison to prevent their attack upon the aftergrowth. Still the young leaves be- came perforated to some extent. The adults, which fly from tree to tree, appeared plentifully without much interruption throughout the season, and often several could be seen feeding on each tree. Possibly many of these may have become poi- soned before depositing the eggs.

The efficiency of London purple being established, it will generally be preferred to other arsenicals, because of its cheapness, better diffusibility, visibility on the foli- age, etc. As the effects of the poisons commonly do not appear decidedly for two or three days after their administration, the importance of the preventive method of poisoning in advance can not be too strongly urged. As the effect isslow in appear- ing, impatient parties will be apt to repoison on the second or third day, and thus put on enough to hurt the plant when the effect does come. Much depends on dry- ness or wetness of the weather; but good effects may be expected by the third or fourth day.

London purple seems to injure the plant less than Paris green.

Treatment with Paris green.—In 1883 the Paris green was first applied on the 29th of May, at which date the eggs were extremely abundant and hatching rapidly on the leaves. Paris green, flour, and water were mixed by the means previously employed with London purple and already described. The mixture was applied to the north part of the same grove of elms. Thus far experience shows that the Paris green is

5 ENT 4

34 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

effective against the insect, but that this poison injures the plant more than does the London purple.

Three-fourths of a pound of Paris green to a barrel (36 or 40 gallons) of water, with 3 quarts of flour, may be regarded as a poison mixture of medium or average strength for treating elms against these beetles, and the indications thus far are that the amount of Paris green should not be increased above one pound or be diminished much below one-half a pound in this mixture. To a bucketful of water three-fourths of an ounce of Parisgreen may be used. The action of this poison is slow but severe, and varies much with the weather. Thus far the results of tests have been varied so much by the weather and different modes of preparation and application that they will be repeated. When used strong enough to cauterize the leaves the poisonous action upou the plant may be observed to continue for several weeks.

The species of Ulmus are quite susceptible to the effects of poison, perhaps as much so as any common species of forest tree. But little can be added to the above quotation, as there are few experiments re- corded concerning work of this kind on other forest trees. With fruit trees and vines there is a large experience, and the results indicate that either of these arsenicals can be safely used on the most tender plants in proportion of 1 pound to 100 gallons of water, if properly atomized. Strong, hardy plants readily stand a strength of 1 pound to 50 gallons of water, if applied with proper care. It is safe to con- clude that between these two. limits a strength suitable for all plants may be obtained.

A thoroughly atomized weak mixture will, under favorable con- ditions, prove as efficient as the stronger ones; but in wet, showery weather weak applications are more liable to be washed off. ¥

_ Properly atomizing the liquid is of the greatest importance, for only by this means can all the foliage be reached. The even distribution thus obtained enables the leaves to retain a greater amount of the poison with less injury than when sprayed in coarse drops.

INSECTICIDES WHICH ACT BY CONTACT.—This class of remedies apply principally to non-masticating insects, 7. e., those which take their food through a sucking-tube or proboscis, such as the plant- bugs, aphids, and scale-insects. They may, however, often be suc- cessfully applied to soft-bodied mandibulate insects, in lieu of the poisonous mixtures.

There are a great. variety of substances, such as alkaline washes and powders, and preparations of oils, and particularly the products of petroleum, which have been successfully used on insects affecting roots, trunks, branches, and foliage of trees. The experimental data concerning them have been mostly obtained from cultivated fruit trees and vines, but they will prove equally available against the similar enemies of forest trees.

Wood Ashes and Lime.—Of alkaline powders, wood ashes aud slaked lime are commonly used either pure or in mixtures around the bases of trees or interred in the earth among the roots of plants to destroy root aphids or other insects affecting the roots. No definite instructions concerning their use can be given, as both substances vary as to strength,

eS ee

and the conditions of application also vary greatly. Unleached wood ashes should not be applied too freely in contact with the body of the tree or the roots, since water leaching through them may contain pot- ash enough to injure the plant. Lime in any reasonable quantity could hardly cause injury. The application of either of these is generally beneficial and tends to destroy and repel insects from the base and roots of trees. The ashes act benficially as a fertilizer.

Coal Ashes and coal Dust.—Coal ashes and coal dust have been used for this purpose, but their effects could only be mechanical, and, while doubtless of value to the plant as a mulching, could have but little effect on insects. The beneficial effects of either of these used dusted on the plant are doubtful, except in cases of soft-bodied slugs (saw-fly larve), where their action is generally good.

Pyrethrum, Hellebore, Sulphur.—These well known insecticides may be used in powdered form or may be mixed with water and applied in aspray- While they can not be recommended for general forest work, cases will frequently arise warranting their use in a limited way against aphids and other soft-bodied insects. Hellebore is of especial value against saw-fly larve. Sulphur is a valuable agent against the red spider (Tetranychus telarius) and may be used alone or in connection with emulsion of kerosene.

Alkaline Washes: potash Lye and soda Lye.—Alkaline washes are solutions of crude soda or potash, or soap preparations of these sub- stances. Concentrated soda or potash lye can be purchased at the stores, and are often used as washes for aphids and coccids with con- siderable success. Of these the potash lye is to be preferred, as its action on the tree is not so harmful as the soda lye. The best possible source of a eaustic wash is the potash lye leached from wood ashes. Crude lye washes should be used with caution, since when too strong it injures both branches and foliage. Definite statements as to the strength to be used can not be made. The different brands of concen- trated lye vary much in composition, so that it will always be advisable to make test applications before general work is attempted. In the preparation of washes, one can (1 pound) of lye is dissolved in from 3 to 5 gallons of water; the stronger solution is very injurious to tender plants, and even the weaker one is entirely too harsh for a safe wash ; yet, if diluted much more, its effect on the insect will be impaired. The same quantity of lye used in the preparation of a soap will give better results, and its use will not then be attended with like danger to the plant.

Alkaline Washes : Soaps.—Soap preparations are made from either of the above lyes with grease or oils of any kind and in my experience are much preferable to the crude lyes.

Any soft or jelly soap makes a good wash for Aphides, and for this purpose need not be strong ; for Coccids the strength should be greater. The preparation known as whale-oil” soap has a more or less stand-

REMEDIES AGAINST FOREST INSECTS. 30

36 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

ard strength and has long been used as an insecticide wash. It is made from various fish-oils and fish-oil residue with caustic soda. Better success attends the use of jelly soaps made directly from fish-oil and concentrated lye, with water, using about three gallons of water, three pints of fish-oil, and one can of lve. Various preparations of this nature can easily be made. Coarse grease does not make so good asoap as oils.

The whale-oil soap sold in the stores is used in solutions of one pound in two to five gallons of water, experiment being necessary to deter- mine what strength will be efficient. The jelly-soap made as mentioned above has been successfully used on Aphides, when fresh, in strength of 1 pound to 8 gallons of water. For most work, however, it would need to be stronger. .

Petroleum Products: Kerosene, Naphtha, etc—Among the washes of an insecticide nature which kill by contact there is probably nothing equal to the preparations from petroleum. Of these it is only necessary to notice those made trom kerosene, as experience has fully demonstrated the value of this product for insecticide work. In most instances either the low or high grade can be used with equally good effect. Kerosene, naphtha and some of the lighter products of petroleum have been used pure.

Naphtha ané the lighter products of petroleum can be used in this man- ner with safety to most plants, but the destructive effect on the insects is by no means Satisfactory. The use of kerosene pure is, however, at- tended with danger and should never be undertaken except in a small way and with the utmost care. Finely atomized, I have employed it with some success, especially on oranges and certain conifers in years gone by, before the emulsions were discovered.

Kerosene Emulsions.—The ease and practicability of emulsifying and diluting kerosene to any desired strength have been so fully demon- strated in the course of the work of the division of entomology under my direction that there is no longer need of attempting its use pure.

The methods of emulsification have been so fully set forth elsewhere that it is unnecessary to undertake their discussion here more than in the nature of general instructions.

An emulsion, if properly made, always contains a greater per cent. of kerosene than of the other ingredients. This per cent. may vary from 60 per cent. to 90 per cent., but experiment has shown that 66 per cent kerosene will give the most satisfactory results.

The formula for the preparatioh of kerosene emulsion ordinarily recommended by me is the one originated by my former agent, Mr. H. G. Hubbard, in his work against orange insects. It is as follows:

IKOTOSONG) oes 2 St oe ee ee Se ee eee ee ee 2 gallons = 67 per cent. Common soap, or whale-oil soap-.-.:.-...-..------------ $ pound Se 33 per cent.

Wiater tite 225 oe S lhl pt Oh Se Re ee Oa eee eee 1 gallon

Dissolve the soap in the water by heating and add the solution, boiling hot, to the kerosene and churn the mixture by means of a

REMEDIES AGAINST FOREST INSECTS. at

force-pump and spray-nozzle for five minutes. The emulsion, if per- fect, forms a cream which thickens on cooling and should adhere with- out oiliness to the surface of glass. Dilute, before using, one part of the emulsion with nine parts of cold water. The above formula makes 3 gallons of emulsion, and when diluted gives 30 gallons of wash.

Resin Washes.—Various compounds of resin and emulsions of resin with kerosene are now being extensively used in California against scale- insects and other enemies of the orange tree. Resin compounds were first used as an insecticide by one of my agents, Mr. Albert Koebele, and his experiments with this substance are given in full in my annual reports as United States Entomologist for 1886 and 1887, and addi- tional experiments by Mr. Coquillett are given in the report for 1888.

Mr. Koebele had good success with the resin compound prepared as follows: Dissolve 3 pounds of sal-soda and 4 pounds of resin in 3 pints of water above fire; when properly dissolved, add water slowly, while boiling, to make 36 pints of compound. <A very strong solution of this was used on pear tiees without injury to the foliage, the solution con- sisting of 3 pints of the compound to 4 of water. Numerous successful experiments were made with one part of the compound and 8 parts of water, and this strength for most purposes will be sufficient.

Mr. Coquillett has found the following to be an excellent formula for the preparation of this compound :*

CO AUISTICISOU Ape ne eet Ae ce mira mee sania bie Seite be Domehee ars Sameldaninds See sets pound.. 1 HROSIN ee Ce ee eee eeierera cee ce ae cacy os iocle emia) siemel see ee Gee aeememewes ene: pounds... 8 RVC T GON BOM ee seein. oo oe ofc eicreia ceice sl Sects, = sels So wre, cine eee eran aioe 6 gallons. .32

Dissolve by boiling the caustic soda in a gallon of water; add the resin to one half the soda solution and dissolve it by boiling; add the remainder of the soda solution and boil over a hot fire, stirring constantly. When sufficiently cooked it will assim- ilate with water like milk, which it much resembles. Add water and strain through a fine sieve.

An emulsion of kerosene with resin compound was satisfactorily ac- complished by taking equal parts of both substances and working them together for two minutes with a pump. This emulsion is not so stable as the emulsion with soap, but is eminently effective against scale- insects and Aphides. At my suggestion the addition of arsenic in the proportion of 1 pound to from 75 to 300 gallons of the resin, or resin and kerosene wash, was made, and this addition was found to greatly increase the efficiency of these insecticides.

The value of these insecticides for the protection of shade and orna- mental trees, which, where scale-insects abound, are as liable to attack and injury as the various fruit trees, need not here be emphasized.

FUMIGANTS—GASES.—The destruction of hot-house pests by fumiga- tion with sulphur, tobacco, or other noxious substances has long been practiced. The application of such methods to trees on a large scale is, however, of recent origin.

The experiments of the last few years conducted by my California agent, Mr. D. W. Coquillett, relating to the use of poisonous fumes or gases against the scale-insects of citrous trees have been attended with

*See Rep. of the U. S. Entomologist for 1888, p. 130.

38 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

such good results that the value of this comparatively new method of combating out-of-door insects is now well established. It is not to be supposed that work of this kind can be carried on in the case of forest trees, except on avery limited scale, to protect cherished trees in lawns or parks. This treatment is also effective against Aphides and leaf- mites—and indeed is calculated to destroy any insects whatever.

Hydrocyanic acid Gas.—Of the several gases experimented with by Mr. Coquillett, of which full accounts are given in my annual reports as Entomologist for 1887 and 1°88, the one named has given much tbe best results.

A number of methods of generating this gas have been devised, of which the most satisfactory is now known as the “dry-gas process.”

The necessity of drying the gas was very evident from the first, for it was found that the injury to foliage was very serious when the gases were charged with any considerable amount of aqueous vapor. In the dry-gas process the cyanide is dissolved by boiling in water for a few minutes, using 1 gallon of water for each 5 pounds of cyanide. To generate the gas, sulphuric acid is caused to flow upon the cyanide solution in a tine stream, causing the gas to be rapidly given off in the form of a whitish fog. The moisture is taken up by passing the gas through sulphurie acid, which by reason of the water taken up becomes diluted, but may still be employed to generate fresh quantities of gas.

The gas is confined to the trees under treatment by meansof a suit- able canvas tent or fumigator, of which a number of styles have been patented. They are constructed so as to be lowered over the tree from above or to inclose it from the sides. Full details for the construction of these tents, together with figures, are given in the reports cited above, to which the reader is referred, also tor a detailed account of the use of various gases. ;

INSECTICIDE APPARATUS.—The application of insecticides to fruit or forest trees may be successfully accomplished by the use of the same devices employed in the case of low-growing plants, except that more force will be required as a rule, and hence larger and stronger machinery. The treatment of young trees or application to the lower part of the trunk or to the base or roots of larger ones may easily be effected by hand, but in the case of the branches and foliage of large trees other means must be employed.

As has been already indicated, the principal insecticides are now used in the liquid form, and particularly in the case of work against the insect enemies of forest trees will this method prove the only prac- ticable one. The use of insecticides in the form of powders will occasion- ally be desirable, however, and hence the treatment of the second part of the subject may be discussed under (1) devices for applying pow- ders and (2) devices for applying liquids.

DEVICES FOR APPLYING POWDERS.—Powder Blowers.—The appli- cation of powders to trees may be successfully accomplished by the use of long-discharge-tube power-bellows.

REMEDIES AGAINST FOREST INSECTS. 39

The Woodason Bellows.—With one of the double-cone bellows manu- factured by Thomas Woodason, Philadelphia, Pa., or other bellows of similar pattern, it is possible to reach branches eight or ten feet high quite readily, and by mounting into the tree, or by means of a ladder, quite effective work can be done on trees ot moderate size.

The Leggett Brothers’ orchard Gun.—Quite recently the Leggett Brothers, of New York City, have invented what they call an “orchard gun,” a machine for the application of powders to foliage beyond the reach of the ordinary hand-bellows.

This device has been tested in the work of the Entomological Division and promises for certain kinds of work to be a very useful implement.

It is constructed of tin tubing 14 inches in diameter made in sections so as to be easily adjusted to any length desired up to 16 feet. On the second section from the base of the device is arranged a small fan 43 inches in diameter propelled by a crank and cog-gearing of such rela- tive diameters that one revolution of the crank gives thirty of the fan. This delivers a strong blast into the distal portion of the tube or gur. Just above the fan is arranged on the upper side of the tube a can 8 inches Jong and 4 inches in diameter, from which the powder fed is into the tube when the crank is turned by the following contrivance:

Between the can and tube is a flat perforated surface its entire leugth, and along this surface plays a set of sliding arms attached to a piston-rod which is thrust forward and backward with each revolu- tion of the crank. This sifts into the tube just the amount of powder necessary to supply a constant but extremely diffuse blast. The short- est working length of the gun is 5 feet, and in this length it serves for all ordinary work of applying powder. The weight of the imple- ment when full length is7 pounds. The length could be easily increased without impairing the efficiency of the implement, except that it would become too heavy and unwieldly.

DEVICES FOR APPLYING LIQUIDS.—For the application of liquids to trees the requisites are a good force-pump and a suitable nozzle, and of both of them there is no scarcity of styles manufactured in this country. In fact, the abundance of pumps, nozzles, and spraying devices tends to confuse the would-be purchaser and makes it the more necessary that the characteristics of a good apparatus should be carefully pointed out.

The Pump.— While secondary in importance to the nozzle, a suitable force-pump is very essential to successful work. As I have previously stated, the nature of the work under discussion precludes the use of any but the more powerful machines, except for comparatively limited operations, where any of the smaller hand pumps, aquapults, hvdro- nettes, or syringes may be used.

In the case of tall trees in parks, such as elms, which frequently attain a height of 40 or 50 feet or more, I have recommended the use of fire en- gines, with which the liquid might be thrown to a considerable distance and, by the force of the discharge, caused to break up into an efficient spray.

40 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

The same end may be more easily attained, perhaps, by using, in con-

chee.

Fic. 7.—Double cylinder brass pump.

@.

nection with a good barrel or tank force-pump, long hose with suitable supports, so that the spray may be brought to bear on the upper por- tion of the tree. Devices for this purpose will be described later on.

Several forms of pumps are be- ing manufactured in this country with which satisfactory work may be done, and in the list of manu- facturers of insecticide apparatus appended to this article are given a number of addresses of reliable firms whose pumps I have used and can recommend.

I will content myself here with describing somewhat fully a force- pump which, in the work of the United States Entomological Com- mission and of the Division of En- tomology, has proved itself well adapted to the purposes desired.

The double Cylinder brass Pump.— The special recommendation of this pump is the more freely given trom the fact that at present no one holds a patent on it and various modifi- cations embracing the essential fea- tures are largely manufactured in different parts of the country. At- tention was directed to the advan- tages of this pump in the work of the commission, and it is illustrated in section and also in operation at plate XLVI of the fourth re- port. The pump, fitted in a barrel with stirrer attachment, there illus- trated,was specially constructed by Dr. Barnard, and has been several times mentioned and illustrated in other official reports.

The appended illustration (Fig. 7) is a sectional view of a similar pump

now in use by the Division.

The essential features of this pump are an outer cylinder a and an jnner cylinder a!, which may be called the piston cylinder. This inner cylinder is provided with a valve, b, similar to the valve int he outer eyl-

REMEDIES AGAINST FOREST INSECTS. 41

inder b! and above the valve D the inner cylinder is closed as shown in the cut. Thus it represents a displacement cylinder and its capacity bears such a relation to the outer cylinder that on the downward stroke it displaces a body of water equal to that taken up by the upward stroke of the piston, thus producing a constant pressure in, a simple single-barreled pump.

The packing d is held in place by a metal follower and fits snugly to the inuer surface of the outer cylinder. The pipe, c,is of rubber hose and made of any length desired to suit the depth of cask or tank and with a fine wire strainer on the bottom. The head of the pump is of cast iron and bulged to allow room for a considerable head of water; iron flanges extend out from its lower part and furnish support by which itis bolted to the tank. All of the working parts arebrass. The packing burr and follower around the upper end of the piston cylinder are the same style as ordinarily used with steam machinery so as to withstand any reason- able pressure. The head to which is attached the compensating bar screws into the top of the piston cylinder. The outlet is tapped through the bulged cast-iron head, and the pressure is much better if a good- sized air chamber is attached to the discharge pipe just outside of the pump head.

The pump from which Fig. 7 was made has two discharge pipes, and one man easily supplies pressure for two ordinary streams of spray.

Fig. 8.—Single-discharge pump.

Fig. 8 shows a similar pump entire, fitted with a single discharge pipe.

42 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

This style of pump is especially convenient from the fact that it can readily be bolted on to a tank of almost any shape or dimensions.

The fulerum post is not cast with the flange-plate, but bolts to it.

The stirrer Pump.—A barrel-tank, with pump similar to the one just described, attached, as used in the work of the commission in the cot- ton-fields, has already been referred to and is figured in the fourth report. :

Hose and Bamboo extension Rod.—The hose commonly used on spray apparatus is half-inch in internal diameter, or even larger. This size is entirely unnecessary and entails extra labor upon the operator ; it is, moreover, quite difficult to get a small extension-rod of any length sufficiently strong to carry such a hose. In the work of the Division of Ento- mology I have found that a good quality of quarter- inch cloth insertion rubber tubing is sufficiently strong for all ordinary work. No spray-nozzle used by hand power will require a stronger stream than this will carry. In some work it is convenient and necessary to have as much as 30 feet of discharge-pipe, and where this small tubing is used it can readily be handled.

For elevating the nozzle among the branches, a bam- boo rod with the septa burned out so that the rubber tubing may be passed through, and made in sections to be adjusted to the desired length, is the most useful contrivance. If this is large enough to admit the tube to pass up the center, and is provided with a clamp at the top to hold the nozzle vertical or in any direction desired, it is superior to any other device which I have ever used. The smaller southern cane, so commonly used for fishing tackle, makes a very good supporting rod, but in such case the discharge-pipe must be fast- ened to the outside by means of suitable spring F1G.9.— Parts of hose clasps.

pole device for

spraying trees: Fic. 9 shows a section of an extension pole of the

bamboo pole, bb;

drip wash’r,j;hose Sort first mentioned above. A special feature of this

hidy clambernes, pole is the washer j, which prevents the drip from

le, nm;spray,2% trickling down the pole upon the operator. It is cut out of a heavy piece of sole leather and fitted snugly over the rod a few inches below the nozzle.

By means of this supporting pole, trees below 20 feet in height can readily be sprayed. For higher trees, I know of nothing better than a ladder mounted on wheels so as to be easily moved from tree to tree, such as has been used in California in the work against the Fluted scale. This ladder is supported so that it does not rest against the « tree, and the operator can move up and down without being hindered

by projecting branches.

s

NSECT

AINST FOREST I

S AG

REMEDIE

Fig. 10.—Spraying outfit in operation as used in orange groves.

44 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Fig. 10 is taken from my annual report as United States Entomologist for 1886. It represents a spraying outfit in operation against the Fluted seale (Icerya purchasi), and indicates sufficiently well the use of the lad- der just referred to, and also of the extension poles.

In Garden and Forest for June 19, 1889, Prof. J. B. Smith, entomol- ogist of the New Jersey experimental station, reports the successful spraying of elm trees in the Rutgers College campus, some of which were over 50 feet high. A Seneca Falls force-pump, provided with some 50 feet of hose, was used. By removing the spraying attachment from the nozzle—a large-size Nixon—the liquid could be thrown in a small stream to a distance of 20 feet. A light ladder gave access to the center of the tree, from which point the extreme tips of the branches could be reached.

Nozzles.—In any device for applying liquid insecticides the nozzle is of prime importance, for on its efficiency will depend in large degree the success or failure of the work. The desiderata in a spray nozzle, as I have elsewhere stated, are ‘‘ready regulation of the volume to be thrown; greatest atomizing power with least tendency to clog; facility of cleansing, or ready separation of its component parts; cheapness ; simplicity and adjustability to any angle.”

Without attempting a general discussion of the merits of different classes of nozzles, I shall content myself with a brief reference to a few styles, which, to a greater or less degree, answer the conditions just enumerated and which have stood the test of practical work.

The Riley or cyclone Nozzle—This nozzle is now so widely known as hardly to require description. As there have been someerroneous state- ments as to its invention, I may take occasion here to reiterate what was recorded in the fourth report of the commission, viz: that if was a devel- opment and outgrowth of my work on the Cotton Worm, the first sug- gestion of the principle being my own and its development resulting

—SS—S>S——————_ fF

NLT, ———— ee ||

| |

Fic. 11.—The Riley or cyclone Nozzle.

from two years’ experimentation under my direction and chiefly through the assistance of the late Dr. W.S. Barnard. ‘Its principal feature con- sists in the inlet through which the liquid is forced being bored tangen- tially through its wall, so as to cause a rapid whirling or centrifugal

Eee ee et

REMEDIES AGAINST FOREST INSECTS. 45

motion of the liquid, which issues in a funnel-shaped spray through a central outlet in the adjustable cap. The breadth or height, fineness or coarseness of the spray depend on certain details in the proportion of the parts, particularly of the central outlet.”

Fig. 11 shows two styles of this nozzle, which I have adopted from a host of experimental forms as the best for all ordinary work. At A is shown the typical small-stemmed nozzle, with the screw cap removed to show the inlet orifice d. At B isshown a sectional view of the same

‘again with the cap removed, showing the tangential entrance to the

chamber a through the orifice e, which when the cap is inserted coincides with the orifice d. At C is shown a face view of the cap ¢, which should be countersunk about the orifice of exit on the exterior surface only ; and also an outline drawing of a chamber placed at an angle of 45° with the stem—a form of advantage especially in overhead spraying.

The stem may be inserted into the discharge-pipe and fastened by wrapping tightly with copper wire, or a more convenient form is made with a female screw of a size to fit a three-eighth inch nipple. The nipple is inserted into the discharge-pipe and fastened in the ordinary manner, and allows an easy interchange of nozzles of different sizes or patterns. A discharge orifice of about one-sixty-fourth of an inch may be used for a very fine spray ; for coarser and heavier work a one-six- teenth-inch orifice will be preferable.

The value of rotating the liquid to break it up into a suitable spray and to prevent clogging, which are the essential features of the Riley nozzle, has been universally recognized.

In this country, owing to the fact that this nozzle has not been pat- ented and is not pushed by interested parties as are patented contriv- ances, it has not come into such general use as its merits warrant or as has accompanied the introduction of patented modifications of it in other countries. It is now, however, being quite extensively manufact- ured and offered by the trade, and a number of modifications of this nozzle have appeared in France, which, while adding certain new feat- ures, have not departed from the valuable principle of the typical form, viz: that of the centrifugal motion of the liquid. These nozzles are employed in France, Germany, and other European countries almost to the exclusion of all other forms, and in this country they are also extensively used. More recently a valuable modification has appeared in this country, the Universal Spray Tip, and in New Zealand a com- pound form is manufactured, known as the New Zealand Triplet, and fashioned after one which I used and described in California in 1887.

A full description of the important modifications of the Riley nozzle that have appeared in this and in foreign countries is given by me in Insect Life, Vol. I, Nos. 8 and 9, to which the reader is referred for fuller details.

In this country, these nozzles are manufactured under contract, for dealers, by Thomas Somerville & Son, Washington, D. C., and by

46 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Woodin & Little, 509 and 511, Market street, San Francisco, Cal. The universal spray tip, the only valuable modification of the Riley nozzle that has appeared in this country, is the invention of and is manu- factured by J. Crofton and L. D. Green, Walnut Grove, Cal.

The addresses of the manufacturers of the foreign modifications of the Riley nozzle are as follows:

The Noél nozzle, by the firm of Noél, Paris.

The Vermorel nozzle, by V. Vermorel, Villefranche (Rhéne), France.

Two modifications of the Vermorel nozzle are:

The Japy nozzle, by Japy Fréres & Cie, Beaucourt, France, and

The Albrand nozzle, by M. C. Albrand, 87 rue dela République, Mar- seilles, France.

The Marseilles nozzle, by L’Avenir Viticole, Marseilles, France.

In New Zealand the Riley nozzle is manufactured by Kutzner Bros., of Masterton, who call it the American cyclone nozzle and make it single and in triplets.

I will call attention here to but one of the most successful of these modifications, which is shown in figure 12. It is known as the Vermorel nozzle, and was devised by a gentleman of that name in France. The

Fic. 12.—The Vermorel Nozzle—natural size (original).

important feature of this nozzle is the pin inserted through its base, bearing on its upper end a point sufficiently small to enter the dis- charge orifice when thrust upward from below. This enables the ope- rator to clean the discharge, when it becomes clogged, and is a great convenience, especially for spraying heavy suspension liquids.

The Nixon or Climax Nozzle.—This is the invention of Mr, A. H. Nixon, of Dayton, Ohio. Its work is so satisfactory, especially where considerable force is required, as will be generally the case in forest work, that I notice it here. A nipple screws on the distal end of a discharge- pipe, and on its outer end is screwed a brass tube varying in length and diameter according to sizeof nozzle. The discharge orifice through the nipple regulates the quantity of spray, and nipples with different sized discharge orifices are interchangeable. The stream projected through this nipple strikes a brass screen at the outer end of the tube and is cut into a perfect spray.

= i 7 a

tA | ll

REMEDIES AGAINST FOREST INSECTS. AT

Cost of a spraying Outfit.—In the foregoing I have presented briefly, yet in sufficient detail, the essential requisites of a good spray apparatus. An entire outfit, embracing the best materials mentioned above, can be gotten together by an ingenious person for a sum not exceeding $20. Outfits may be purchased from manufacturers at prices ranging from $20 to $50, according to sizes or styles.

A list of responsible firms with whom the Division of Entomology has had business relations is here appended :

W. & B. Douglass, Middletown, Conn.; Rumsey & Co., Seneca Falls, N. Y.; Field Force-Pump Company, Lockport, N. Y.; Robert T. Deakin & Co., Philadelphia, Pa.; Nixon Nozzle and Machine Company, Dayton, Ohio; Woodin & Little, San Francisco, Cal.; The Gould’s Manufactur- ing Company, Seneca Falls, N. Y.; Thomas Woodason, 451 East Cam- bria street, Philadelphia, Pa.; Leggett & Brother, New York.

CHAPTER I. INSECTS INJURIOUS TO THE OAK.

Various species of Quercus.

The oak perhaps affords our most valuable lumber, whether ship- timber, carriage wood, or when used for carved work, floors, or furniture. As a shade tree it will always be in demand, while groves oi oaks are among the chief ornaments of parks. The oak can be easily planted, and it is one of the trees most available in the renewal of our forests.

Unfortunately the oak is preyed upon by a larger number of kinds of in- sects than perhaps all the other hard-wood forest trees mentioned in this work put together. From the roots to the extremity of the smallest twigs, including the buds and acorns, there are assemblages of insects which divide the arboreal territory among themselves, not often encroaching on each other’s domain. In this way the work of destruction often be- comes thoroughly welldone. Yet, considering the number of species of insects which prey upon this devoted tree, particularly when isolated from . its fellows, it is a wonder how evenly preserved is the balance of nature. Undoubtedly, as in all other trees and most vegetable growths, a cer- tain amount of natural, healthy pruning is accomplished by insects. But were there not a complicated system of checks, particularly those due to parasitic insects and to unfavorable climatic changes, the tide of insect life would sweep away every tree and shrub from the face of the earth.

In his work on Plant-Enemies of the Class of Insects,” Kaltenbach enumerates five hundred and thirty-seven species of insects of all orders which in Germany prey upon the oaks of that empire.

It is probable that nearly if not quite as many will be found in a re- gion of the same extent in this country, especially since the species of oaks are more numerous in the eastern United States than in central Europe, the number of species in the latter region being but two or three to twenty in the United States, east of the Rocky Mountains.

The number of determined species of oak insects recorded in the fol- lowing pages is over 400, while the number of undetermined species would carry the number up to over 500, or about as many as Kaltenbach

48

wee ae cree

INSECTS AFFECTING OAK-ROOTS. 49

records forGermany. It is not improbable that ultimately the number of species for the United States will be between 600 and 800 or even 1,000.

We will now briefly indicate those species of insects which are habit- ually more or less destructive to the oak.

The roots of the live and probably the water oak are infested by the great longicorn borer, Mallodon melanopus, the trees being permanently dwarted and their growth arrested.

Of the borers in the trunk, the caterpillar of the Carpenter moth (Prionoxystus robinic) probably does more damage than all other borers combined. Next to this borer, come the flat-head borers, and the bark- borers, with the oak-pruner (Hlaphidion villosum), while the seventeen- year Cicada periodically prunes or destroys many of the twigs.

The leaves suffer most from the attacks of the forest tent-caterpillar (Clisiocampa disstria) and the large black-and-red-striped spiny cater- pillar of the senatorial moth (Anisota senatoria). These two caterpillars in the Atlantic and Central States as a rule do more harm to oak for- ests than perhaps all the other species combined.

Finally, many acorns are worm-eaten, the intruder being the grub of the long-snouted weevil (Balaninus). We have, so far as practicable, described the habits and appearance of the most destructive species first.

AFFECTING THE ROOTS.

The roots of various species of oak are, without much doubt, more or less injured by the attacks of the seventeen-year Cicada while in its preparatory state, as it is known that this insect, so abundant in the central and southern States of the Union, remains for over sixteen years attached by its beak to the rootlets of the oak and probably other forest trees, where it sucks the sap, thus in a greater or less degree in- juring the health of the tree. Observations as to the subterranean life of the seventeen-year locust are few and obscure, and it is quite uncertain how much injury is really done to trees by this habit. They have sometimes been found sucking the sap of forest trees, notably the oak, and also of fruit trees, snch as the pear and apple. According to Riley (First Report, p. 24), the larve are frequently found at great depth, sometimes as much as 10 feet below the surface. It has been claimed by Miss Margaretta H. Morris, in an account published in 1846, that pear trees have been killed by the larve sucking the roots. This has been denied by the late Dr. Smith, of Baltimore, who says:

The larva obtains its food from the small vegetable radicels that everywhere per- vade the fertile earth. It takes its food from the surface of these roots, consisting of the moist exudation (like animal perspiration), for which purpose its rostrum or snout is provided with three exceedingly delicate capillaries or hairs, which project from the tube of the snout and sweep over the surface, gathering up the minute drops of moisture. Thisis its only food. The mode of taking it can be seen by a good glass.— Prairie Farmer, December, 1851.

5 ENT 4

50 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Dr. Riley adds that Dr. Hall, of Alton, Ill, has often found them firmly attached to different roots by the legs, but never found the beaks inserted. He remarks as follows :

The fact that they will rise from land which has been cleaned of timber, cultivated, and even built upon for over a dozen years, certainly contravenes Miss Morris’s state- ment, while their long subterranean existence precludes the necessity of rapid suc- tion. Itis also quite certain that if they thus killed trees we should oftener hear of it, and I have captured a gigantic but unnamed species of Cicada on the plains of Colorado, 50 miles from any tree other than a few scattering willows.

We would add that in June, in Idaho Territory, we have seen numer- ous Cicadz which had just appeared above the surface of the earth in a desert region with scattered sage bushes, upon whose roots, which it is known descend to a great depth, the young may feed. While, then, the Cicada may seldom do marked injury to the oak, the reader is re- ferred to a subsequent page for a further notice of the injury done by this insect to the twigs and smaller branches of the oak and other trees.

In Europe the roots of oaks are affected by a small wingless gall-fly, which punctures the root and inserts an egg into the hole. The irrita- tion set up by the presence of the larva causes the root to swell until a tumor or gall is formed, in the center of which lies the white footless larva or maggot of the fly.

Fitch has found similar wingless flies in this country, but they will always remain objects rather of a scientific than economic interest. He has described them under the names of Biorhizanigra, Philonix ful- vicollis and nigricollis. They are wingless, and occur in forests in No- vember and December, often walking on the snow in company with other snow insects, such as Boreus and Chionea. There is also a root gall, of which Professor Riley has detected aspecies. The known species of root-galls are enumerated in Mr. Ashmead’s catalogue of Cynipide, reprinted further on in this chapter, at the end of the section on insects infesting oak twigs.

1. THE LIVE-OAK ROOT-BORER. Mallodon melanopus Linn. (Larva. Pl. xxxv, Fig. 1.)

Boring under ground in the roots of the live-oak and dwarfing the young trees in Florida and the Gulf States; a very large white grub, transforming to a large brown longicorn beetle.

While in Florida, at Crescent City, | had an opportunity, owing to the kindness of Mr. H. G. Hubbard, of collecting the grubs (described below) and seeing the injury done by this borer to the live oaks.

The following account is taken from Professor Riley’s report for 1884:

This beetle is one of our largest insects, being about two inches long and very broad and heavy. Its larvais a cylindrical grub, or ‘‘sawyer,” about an inch in thickness and over three inches in length.

In Texas Mr. Schwarz found the larva of this Mallodon excavating its galleries in the heart-wood of the Hackberry (Celtis), a tree of the largest size. In Florida and elsewhere it feeds upon the live-oak, and it would seem that so large and powerful a borer was well chosen to be the destroyer of this giant among trees.

OAK-ROOT BORERS. 51

In point of fact, however, in its connection with this tree the beetle shows a sur- prising modification of its recorded habits. Its larva is found, not in the stem of the mature tree so justly celebrated for its strength and toughness, but always in the root of infant trees, and usually in degenerate highland varieties of Quercus virens, or of its relatives, Q. aquatica and Q. catesbei.

The mother beetle selects small saplings as a place of deposit for her eggs, which are laid in the foot, or collar, of the tree, just below the surfaée of the ground. How long a larval existence the insect has is not known, but it must extend over several years, since the roots occupied by these larve grow to a large size, while at the same time they show an entirely abnormal development and become a tangle of vegetable knots. In fact, the entire root inits growth accommodates itself to the requirements of the borer within. Very few new roots are formed, but the old roots excavated by the larva are constantly receiving additions of woody layers, which are in turn eaten away and huge flattened galleries are formed, which are for the most part tightly packed with sawdust.

The beetle thus becomes, not the destroyer, but the parasite of the tree, and lives in a domicile, which may not improperly be termed a gigantic root-gall. The effect on the tree is to kill the original sapling, which becomes replaced by a cluster of in- significant and straggling suckers, forming perhaps a small clump of underbrush. In many cases the branches and leaves are barely sufficient to supply the materials . for sluggish growth, and the entire strength of the plant goes toward the formation of a root plexus, out of all proportion to the growth above ground, and plainly de- signed to repair the ravages of the borer.

The Mallodon borers are very abundant in South Georgia and Florida, and asa result of their attacks, vast tracks which might otherwise have become forests, en-| riching the ground with annual deposits of leaves, are reduced to comparatively bar- ren scrub, in which the scattered oak bushes barely suffice to cover the surface of the sand.

Many a new settler, seeing his sandy hill-side covered only by insignificant oak bushes, and anticipating easy work in converting the wilderness into a blooming garden of orange-trees, has been grievously disappointed to find before him no light task in clearing from the soil these gnarled and tangled roots. In fact the great strength and weight of the southern grubbing-hoe appears no longer a mystery when one contemplates the astonishing pile of “grub roots” which in vigorous hands it will extract from a few square rods of apparently unoccupied soil.

The results of the work of this beetle are very plainly visible around Savannah, and especially on Tybee Island, where Mr. George Noble first drew our attention to it; while Mr. Hubbard has carefully studied its work, as here recorded, in Florida. (Riley’s report, 1884.)

The genus Mallodon contains species of large size with the sides of the prothorax | armed with numerous small teeth. The head is comparatively large, the eyes strongly granulated, distant, transverse, feebly emarginate. The antennz are slender, not exceeding half the length of the body in the male and shorter in the female. The sexual differences are worthy of note. ‘The prothorax in the male is nearly quadrate, densely punctured, with smooth separate facets, while in the female it is narrowed in front, more coarsely punctured towards the sides, and uneven on the disk.

The present species is distinguished by the decidedly serrate prothorax, while the tibiz are densely ciliated on the lower edge. It is dark brown, almost black. Length, 45 to 55™™, (1.75 to 2.25 inches). It inhabits Florida, Arkansas and Texas.— (Horn. )

Larva.—Body as large and thick as one’s forefinger. It closely resembles the larva of Orthosoma brunneum* in general appearance and proportions, but considerably thicker. Shape of the prothoracic segment and size of the head and shape of the

* | have no larva of Prionus laticollis with which to compare it, and which it may more closely resemble than Orthosoma.

52 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

mouth-parts much asin Orthosoma. Dorsal prothoracic plate and the segment be- neath as in Orthosoma, but on each side in front of and above the prothoracic feet is a large hairy tubercle of which Orthosoma has no traces. The remaining segments of the body above and beneath are almost identical in form and markings with those of Orthosoma, The callosities on the upper side of the abdominal segments differ slightly in having the transverse areas not divided by a median impressed line, as they are in Orthosoma (see Pl. xxxv, Fig.1). The thoracic feet as in Orthosoma, but the spiracles are much larger in proportion.

Head as in Orthosoma, except that the front edge of the epicvranium next to the clypeus is smooth and straight, not dentate, as in Orthosoma (Pl. xxxv, Fig. 1a). Clypeus and labrum identical in form with those of Orthosoma, but the stiff bristles on the front edge of the labrum are considerably longer. Antenne three-jointed and asin Orthosoma, as is the shape of the labium with its two-jointed palpi; the latter, how- ever, much stouter, though not reaching beyond the end of the labrum. Maxillx as in Orthosoma, but the four-jointed palpi are a little stouter. Length of body, 87™™ (325 inches); breadth of prothoracic segment, 20™™,

2, THE BROAD-NECKED PRIONUS.

Prionus laticollis (Drury).

Fic. 13.—Broad-necked Prionus, its larvaand pupa. After Riley.

Though usually living in the roots and trunks of the poplar and balm- of-Gilead, Mr. F. Clarkson states that at Oak Hill, Columbia County, N. Y., this borer infests the black oak, the beetle emerging at twilight during the first two weeks in July.

Their presence is quickly realized by the odor of the female, which is very power- ful, and can readily be detected 20 feet distant. I placed a female immediately

after emergence in an uncovered jar, and wherever I positioned it, on the piazza or elsewhere, the males were attracted from every direction. I captured twenty males

OAK-BORERS. 53

in a very few minutes. Oak Hill can not boast of a balm-of-Gilead or a Lombardy pop- lar, but it is famous for its eaks, and while it is admitted that the former trees, as mentioned by Harris, serve as food for the larv, my observations indisputably prove that they feed also upon the roots of the oak. (Can. Ent., xvi, 95.)

AFFECTING THE TRUNK. 3. THE OAK CARPENTER WORM. Prionoxystus robinie (Peck). Order LEPIDOPTERA; Family Cossip#&.

Boring large holes and galleries in the trunk; a large, livid, reddish caterpillar, nearly three inches long, greenish beneath, and the head shining black; the body somewhat flattened, and with scattered long, fine hairs. The chrysalis also in the burrow, and transforming to a large, thick-bodied moth in June and July.

In different parts of New England, from Maine to Rhode Island, and southward to Texas, oak lumber and cord-wood is commonly seen to be often honeycombed by the large black burrows of this common and destructive borer. It is the most directly injurious of all the insects preying on this noble tree, since it sinks its tunnels deep in towards the heart of the tree in the living wood, and is a difficult insect to discover until after the injury is done. It may be found in the autumn and winter months, of different sizes, showing that at least there is an interval of one year between the smaller and larger sizes, and that consequently the moth is two, and probably three years in attaining maturity.

Fic. 14.—Larva and pupa of female, and male imago of Oak Carpenter Worm—all natural size. After Riley.

The female moth, without doubt, lays her eggs in the cracks and interstices of the bark of the oak or locust, in the latitude of Boston, about the middle of July.

I have taken the larva and chrysalis from the red oak in Maine, and the insect occurs westward to the Mississippi Valley and southward to Bosque County, central Texas. At Houston, Tex., I have found a dozen

54 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

or more of the cast chrysalid skins projecting from the stumps of the pin oak; one pupa was alive early in April. It is said by Fitch to bemore common in the Southern and Southwestern States than in the Northern. It is also an inhabitant of California, and may be found to occur in nearly all the United States wherever the black, red, and white oak or locust trees grow. The habits and metamorphoses of the moth were first discovered by Peck,* who bred it from caterpillars found in the locust, but Harris afterward discovered that it ‘‘ perforates the trunks of the red oak.” Bailey states that it also feeds on the willow. (Bull. No. 3, Div. Ent., U. S. Dept. Ag., p. 54).

Riley states that the male caterpillar is only half as large as the female. He adds that with her extensile ovipositor the moth deposits her eggs in the deep notches and dark bottoms of crevices. ‘The young worms which hatch from them are dark brown with large heads ; they are active and commence spinning as soon as they are born” (Amer. Ent., 11, 127). He finds it more partial in the West to the locust than to the oak. ;

The following account of its habits and transformations is copied from Fitch:

Of all the wood-boring insects in our land this is by far the most pernicious, wound- ing the trees the most cruelly. The stateliest oaks in our forests areruined, probably in every instance where one of these borers obtains a lodgment in their trunks. It perforates a hole the size of a half-inch auger, or large enough to admit the little finger, and requiring three or four years for the bark to close together over it. This hole running inward to the heart of the tree, and admitting the water thereto from every shower that passes, causes a decay in the wood to commence, and the tree never regains its previous soundness.t

This is also a most prolific insect. The abdomen of the female is so filled and dis- tended with eggs that it becomes unwieldy and inert, falling from side to side as its position is shifted. A specimen which I once obtained extruded upwards of three hundred eggs within a few hours after its capture, its abdomen becoming diminished hereby to nearly half its previous bulk; and in the analogous European species more than a thousand eggs have been found on dissection. It hence appears that a single one of these insects is capable of ruining a whole forest of oak trees. This calamity, however, is prevented, probably by most of the eggs being destroyed, either by birds or by other insects, for these borers are by no means 60 common in our trees as the fecundity of their parents would lead us to expect.

Our moth comes abroad, as already stated, in June and the forepart of July. It flies only in the night time, remaining at rest during the day, clinging to the trunks of trees, its gray color being so similar to that of the bark that it usually escapes notice. In repose its wings are held together in the shape of a roof, covering the hind body. From observing her motions in confinement, I think the female does not insert her eggs into the bark, but merely drops them into the cracks and crevices upon its outer” surface. They are coated with a glutinous matter which immediately dries and hardens on exposure to the air, whereby they adhere to the spot where they touch ; and if the short two-jointed ovipositor be not fully exserted as the egg is passed

* Mass. Agr. Report and Journal, Vol. v, p. 67, with a plate, 1818,

+ We have observed that the old burrows are lined by a dark layer, consisting of a mealy débris about as thick as pasteboard; this detritus is probably composed of the castings of the larva, which form a paste that in drying strongly adheres to the sides of the gallery.—A. S. P.

:

OAK-BORERS. 55

through it, so as to carry the egg beyond the hair-like scales with which the body is clothed, some of these touching adhere to it, their attachment to the body being so slight.

The eggs are of a broad oval form, and about half the size of a grain of wheat, be- ing the tenth of an inch in length and three-fourths as thick, of a dirty whitish color with one of the ends black. When highly magnified their surface is seen to be retic- ulated or occupied by numerous slightly impressed dots arranged in rows like the meshes ina net. From the fact that several worms of the same size are sometimes met with in a single tree, indicating them all to be the progeny of one parent, it ap- pears that the female drops a number of eggs upon each tree that she visits, and prob- ably disposes of her whole supply upon a very few trees. The size of the eggs doubt- less renders them a favorite article of food to some of our smaller birds. And a bird in discovering some of these eggs will be incited thereby to search for others in the same vicinity, which search being successful, will be perseveringly continued so long as an egg can be found upon that or any of the adjacent trees. Thus it may be that of the whole stock of eggs which a female deposits, scarcely one escapes being picked up and devoured. This appears the most probable cause of so. few of these worms being met with, although the females are so prolific.

The worm on hatching from the egg sinks itself inward and feeds at first on the soft inner bark, till its jaws acquiring more strength it penetrates to the harder sap-wood and finally resorts to the solid heart-wood, residing mostly in and around the center of the trunk, boring the wood here usually in a longitudinal direction, and moving backwards and forth in its burrow, enlarging it by gnawing its walls as it increases in size, whereby the excavation comes to present nearly the same diameter through its whole length. In an oak in which I met with two worms fully grown and several others but half grown, the whole of the central part of the trunk had been exten- sively mined by preceding generations of this insect and was in a state of incipient decay ; and I thus had an opportunity to notice the fact that none of the worms were lying in the decaying wood, all being outside of this, where the wood was still sound, Hence it is evident that it is living healthy trees which this insect prefers, and not those which are sickly and devaying, which latter are preferred by the European Cossus, some authors say, though perhaps their observations have not been exact upon this point, for in the instance here alluded to it would have been said on a first glance that these worms preferred decaying wood, since the diseased heart of the tree was everywhere traversed with their burrows, and the sound wood showed few of them; and thus no doubt in many other cases we mistake the cause for the effect, and on seeing semi-putrid wood filled with worm-holes, we suppose the worms have-preferred wood of this character, when in truth it is these holes which have caused the decay of the wood.

These worms are probably three years in obtaining their growth. They cast off their skin several times, and after the last of these moltings their color becomes different from what it has previously been.

The larva previous to the last change of its skin is of a rose-red or a pale cherry- Ted color, often with a faint yellowish stripe along the middle of its back, on all except the three anterior rings. It is of a cylindrical form, slightly broadest ante- riorly and a little flattened beneath. It is divided by transverse constrictions resem- bling broad shallow grooves into twelve rings, which are twice as broad as long. On each of these rings are a few pimples of a deep purple color, regularly placed, each giving out a pale-brown bristle. Fourof these pimples are on the back, placed at the angles of an imaginary square or a trapezoid having its hind side the longest, the two hinder pimples being larger. Small white dots confluent into broken lines may also be perceived, forming a transverse square in which the two anterior pimples are inclosed, and other dots less regularly placed surrounding the two hind pimples except upon their hind side. Above the breathing pores on each side is also a large pimple, which, upon the four rings bearing the prolegs, has a white dot in its lower edge, which dot does not appear in the corresponding pimples of the other rings. A

56 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION

minute pimple is also seen forward of the upper end of each breathing pore, below which all the under side of the worm is greenish white. The breathing pores are oval and light yellow, with a rusty brown oval spot in their center and a dark purple ring around their outer edge. Below them the skin bulges out, forming a longitudinal ridge, or rather two parallel ridges divided by adeep intervening furrow. Upon the upper one of these ridges near the middle of each ring is a round cherry-red spot in which are two small pimples, and on the lower ridge is a single one, placed farther back, whilst four others equally minute may be seen farther down and around the anterior base of the prolegs. The second and third rings are shorter, each with four- teen pimples of different sizes, the larger ones forming a single transverse row. The first ring or neck is polished and of a dark tawny brown color on its upper side, with a white line in its middle disappearing anteriorly in a black two-lobed cloud. The head is but half as broad as the body, andisof a shining black color, tinged more or less with chestnut brown in its middle, with scattered punctures from which arise fine hairs. The antenne are chestnut brown, conical and three-jointed, the last joint minute, with a bristie beside it given out from the apex of the second joint. The palpi are similar, with two small processes from the summit of their second joint, the outer one of which ends in a minute fourth joint. Of the eight pairs of legs, the three anterior are conical and end in a single chestnut-colored claw. The others are short, thick, and retractile, with their soles surrounded by a blackish fringe-like ring composed of a multitude of minute hooks, the last pair, however, having these hooks. only around the anterior and outer half of their soles. Placed in a glass or tin vessel, this worm is perfectly helpless, being unable to cling with these hooks to a hard smooth surface.

With the last change of its skin it loses its bright-red color and is then white, tinged with green at the sutures, and with a pale-green stripe along the middle of its back, which disappears at the sutures. The pimplesare of a pale tawny yellow color with black centers. The head is light tawny yellow varied in its middle with greep- ish white, its anterior edge blackish and the jaws deep black.”

As the moth into which this worm changes possesses no jaws or other implements by which it is possible for it to perforate the wood, it is necessary for the worm to pre- pare a way for its future escape from the tree ; and the provisions which it makes for this end are truly interesting, indicating that the worm has a clear perception of what its future condition and requirements will be, both in its pupa and its perfect state. This is the more surprising when we recur to the fact that since its infancy this crea- ture has been lying deeply bedded in the interior of the tree, the only act of its life having been to crawl lazily around in its cell and gnaw the wood there when impelled by hunger. How does it now come to do anything different from what it has been doing for months and years before? But, having got its growth and the time draw- ing near to have it change into a pupa or chrysalis, we see it engaging in anew work.

It now bores a passage from the upper end of its cell outward through the wood and -

bark till only a thin scale of the brittle dead outer bark remains, It is usually at the bottom of one of the large cracks or furrows in the bark that this passage ends,

* Received full grown larve from F. G. Mygatt, Richmond, Ill., February 26, 1868, found boring in a large black-oak tree, forming their cocoons soon after the receipt. The male larve have generally broken bands of reddish brown across the middle of each segment. The female larve are perfectly fulvous or of the color of ordinary yellow butter; subcylindrical; thoracic segments broadest, tapering thence to anus. Segment 1 flatter than the rest; head polished brown and fulvous; pilifer- ous spots variable in size, being more distinct when young, and often connected by transverse bands of brown; stigmata brown, large, and distinct; feet and legs same as venter, the former with brown extremities, the latter fringed with brown; anal segment more glaucous than the rest. Others were received from J. M. Shaffer, January, 1870, found boringin black locust, and were exactly like the oak-feeding specimens. (Riley’s unpublished notes. )

OAK-BORERS. 57

whereby the hole inside is less liable to be discovered by birds. The worm then dili- gently lines the walls of this hole with silken threads interspersed with its chips and forming a rough surface resembling felt, as it withdraws itself backwards for a dis- tance of about three inches, thus placing itself beyond the reach of any bird or other enemy outside of the tree, should its retreat be discovered; and it here incloses itself in a cocoon which it spins of silk, of a long oval form, having the end towards the outer opening much thinner and its threads more loosely woven. In this cocoon it throws off its larva skin and then appears in its nymph or pupa form.

The pupa is an inch and three-quarters long and half an inch thick, of a dull chest- nut color, the rings of its abdomen paler, and on the back near the anterior edge of each ring is a row of angular teeth, resembling those of a saw, of a dark brown color and all of them inclining backward, these rows of teeth extending’ downwards upon each side below the breathing pores or about two-thirds of the distance around the body. On the middle of each ring is also a much shorter row of little tubercular points. Finally, upon the under side of the last segment are about four stouter conical teeth, the tips of which are drawn out into sharp points which are curved forward, so that when this last segment, which is tapering and smaller than the others, is bent down- wards these curved points will catch and hold the body from moving forward.

The pupa lies perfectly dormant in its cocoon probably a fortnight or longer. - It then awakes from its slumbers and begins to writhe and bend itself from side to side. By this motion the rows of little teeth upon the rings of its abdomen, which incline backward as above described, catch in the threads of the cocoon, first upon one side and then upon the other, and thus move the body forward, whereby its head presses upon the loosely woven end of the cocoon, more and more firmly, until it forces its way through it, and the pupa works itself forward out of its cocoon. And the same writhing motion being continued, the teeth now catch in the threads with which the sides of the hole are lined, and thus, though destitute of feet, the pupa moves itself along till it reaches and breaks through the thin scale of bark which hitherto has closed the mouth of its burrow, and pushes itself onward till about three-fourths of its length protrude from the tree, when by curving the tip of its body downward the four little hooks thereon catch in some of the threads and hold it from advancing further and falling to the ground. By so much motion of the pupa the connections of the inclosed insect with its shell become sundered and the sutures of the shell are probably cracked open, so that the moth readily presses them apart and crawls out therefrom, leaving the empty and now lifeless shell projecting out from the mouth of the hole, with a small mass of worm-dust surrounding it.

The male moth is of a gray color from white scales intermixed with black ones. The head is furnished upon the crown, or vertex, with longer or hair-like scales. The antenn® are tapering and many-jointed, their basal joint thickest and covered with black and gray scales, the remaining joints being naked, shining, coal-black, each joint bearing two branches on its front side, forming two rows of coarse teeth like those of a comb, the teeth being six or more times as long as thick, and all of the same length except at the base and tip, where they become shorter, all of them ciliated with fine hairs. The feelers are appressed to the face and reach as high as to the middle of the eyes, and are cylindric, clothed with short appressed scales, the separation of the terminal joint being slightly perceptible. The thorax has the shoulder-covers black, forming a stripe of this color along each side, which anteriorly curves down- wards and is continued backward upon the upper side of the breast. Its base is clothed with larger scales, forming tufts upon each side. The abdomen is conic and equals the tips of the wings in its length, and is but slightly covered with scales except along each side, where they form a broad stripe, the under side being eutirely de- nuded; it is black and shining, with the sutures dull yellowish. At its tip are three appendages, longer than the last ringsof the abdomen. The two lower ones are broad, thick, flattened processes of a dull brownish yellow color, with their tips rounded and slightly bent inwards towards each other. The upper one is a slender, black, shining hook or claw of the same length, its tip sharp-pointed and curved downward. Above

58 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

these appendages and hiding them from view is a brush of black hairs, forming a con- ical tuft at the end of the abdomen, blunt at its apex. The legs are more or less denuded of scales, black and shining, with the hind shanks thicker toward their tips and with two pairs of spurs, the forward shanks having only a single spine, which is placed on the middle of their inner sides, the same as in other moths ; and the feet are compressed and five-jointed, with the basal joint longest and the following ones suc- cessively shorter. The fore wings are black, with groups of whitish scales forming gray spots or clouds which are netted with black lines, varying greatly in different individuals. Often a transverse gray spot is situated towards the base and another on the anal angle, the outer and hind margins being gray alternated with black. The hind wings are black, with their posterior half of arich marigold yellow color bordered with a black line upon the hind margin, the yellow color being irregularly notched on its anterior side and narrowed to the inner angle, and not extended to the outer angle, the two outer cells being black. The outer or anterior margin, except at its base and tip, is usually gray alternated with transverse black streaks and blotches, and inside of this isa large ash-gray spot occupying the outer anterior part of the disk. The under sides of both wings are similar to their upper surface.

The female would not be supposed to pertain to the same species with the male, her size is so much larger, her colors so much paler gray, and her hind wings being wholly destitute of the bright yellow coloring which forms so conspicuous a mark in the other sex. The branches of her antenne are also’shorter, being but about four times as Jong as thick. The ground color of her fore wings is gray, variously netted with black lines dividing the gray in places into small roundish spots and into rings hav- ing black centers. The black color usually forms a broad irregular band across the middle of the wings parallel with the hind margin, and another between thisand the hind edge, chiefly on the outer half of the wing, the hind edge and fringe being whitish alternated with black spots placed on the tips of the veins. The hind wings are dusky gray and towards their bases blackish, their posterior half being freely transparent and faintly netted with darker lines. The body is densely coated with gray scales, its under side hoary white; and the legs are gray, with black bands on the shanks, and black feet, with gray rings at their articulations.

Remedies.—We have but a single suggestion to make upon the subject of remedies against this truly formidable though fortunately rareenemy. Itis probable that soft soap applied the fore part of June to the bodies of trees will be equally efficacious against this and other borers as it is against that of the apple tree. This remedy may well be resorted to, to protect the locusts and oaks which we value as ornamental trees; and scarce and valuable as timber is becoming in all the older settled sections of our country, I doubt not it will be found to be good economy to bestow similar attention upon the more valuable trees standing in our forests.

It should also be observed that whenever a hole made by a borer is discovered in the trunk of a tree, it should be immediately closed by inserting a plug therein, to exclude the wet which will otherwise be admitted hereby to the interior of the tree and produce a decay of the surrounding wood.—(Fitch’s Fifth Report, pp. 4-10.)

4, THE LESSER OAK CARPENTER WORM. Prionoxystus querciperda (Fitch). Order LEPIDOPTERA; Family CossiD2. (Pl. 11, Figs. 4, 5.) Another and rather smaller Cossid, but belonging to a closely allied species, was found by Mr. J. A. Lintner resting upon the trunk of an oak tree in Schoharie, N. Y. It probably ranges all over the Eastern

States and Mississippi Valley, since a species, either this or closely allied, is reported to us by Mr. G. W. Belfrage to inhabit central Texas. Dr.

7 f

eo

OAK-BORERS. 59

Fitch thinks it probable that it bores into the oak. He describes it as a moth smaller in size than P. robinice, with thin and slight transparent wings, which are crossed by numerous black lines, the outer margin only of the forward pair being opaque and of a gray color; the hind wings of the male are colorless, with the inner margin broadly blackish and the hind edge coal-black.

Mr. Lintner has found the larva burrowing in the black oak. The moth appeared April 29th. The male is about half as large as the female.

‘This species is smaller than robinic, the female expanding 46™™ or 47™™, the male about 10™™ less. The male hind wings seem translucent, but on holding them obliquely in certain lights the yellow tint may be seen plainly. This smaller and rarer species occurs also in Texas. It is freer from reticulations and more transparent than any other form.” (Bailey, Bull. No. 3, Div. Ent., Dept. Ag., 55.)

Larva.—Length an inch and a half. Pale green, with a darker green dorsal stripe, bordered faintly with yellow. Head flat, subtriangular, dark brown clouded with black. First segment with two brown spots extending across it, narrowed laterally, and of nearly the length of the segment medially, where they unite to inclose on the dorsal line an elongate-elliptical green spot. The anterior segments are flattened, and broader than the following, which gradually diminish in breadth toward the posterior end. The segments are marked dorsally with four rose-colored elevated points, the trapezoidal spots of Guenée; on the 10th and 11th segments they form a quare. A similar spot is present above each stigma, a smaller one below, and an- other in front—each of these bearing a short brown hair. The stigmata are oval, orange-colored, centered with dark brown. Thelegsare tipped with chestnut brown, and the prolegs armed with brown plantz.—(Lintner, Ent. Contributions, iv, 135.)

5. Cossula magnifica Bailey. (Pl. 11, figs. 1-3.)

An account of this fine moth and its transformations is published in Papilio (ii, 93) by Dr. J. S. Bailey. The larve were found by Mr. Koebele boring in species of oak and hickory near Tallahassee, Fla. A single live-oak was observed standing in an open field containing many larve, their debris, resembling saw-dust, being distributed over the ground around the roots of the tree more than six inches in depth. ‘At the period of pupation the larvee, as is customary with the Cosside, takes its position near the surface of the bark. The tunneling is usu- ally conducted near the surface, from one-quarter to one inch beneath the bark. After the imagines emerge their pupa cases are left protrud- ing through the bark.”

Pupa.—The long testaceous pupa-case is provided with an irregular series of five tuberculations on each side ef the anus. (Bailey.)

Moth.—Size small; male antennz bipectinate to the tips, the inner series one-third the length of the outer pectinations; hind tibize pilose; wings broad, the front pair rounded at the apices, costa with dark dots; fuscous gray, smooth, with indistinct fragmentary reticulations. A light brown patch covers the outer edge; before the patch is a light gray subterminal shade. Hind wings blackish brown; front yellow- ish; thorax light gray; abdomen dark gray; expanse of wings, 36™™, (1.44 inches). ( Bailey.)

60 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

6. Cossus reticulatus Lintner.

This moth was described by Mr. J. A. Lintner, from a single female in the collection of Mr. Neumogen, collected in Texas, on the Rio Grande. Mrs. Slosson has observed it riddling live oaks in Florida.

Allied to C. robinie in shape of wings and markings, having the stronger scales and reticulated ornamentation of that species, in which it differs from the minute and sparse scales and transverse lines of C. querciperda and C. centerensis.

Primaries reticulated with black on a pale ash ground, the wings lighter than in C. robinie, from the absence of the conspicuous intranervular black spots and streaks which characterize that species, and are well represented in fig. 205, p. 413, of Harris’ Insects Injurious to Vegetation. In this species, only between the internal, submedian and 1st median venule (veins la, 1b, and 2), at the outer third of the wings, do the reticulations coalesce so as almost to form spots. In the terminal and subterminal por- tions of the wing, the small ash spots (sometimes ocellated with a black dot or line) for the greater part rest upon the veins; between 2 and 5, there are other spots in- termediate to these venular ones; elsewhere, with a few exceptions, the spots are venular, forming two intranervular rows. The costal region is pale ash, traversed by black lines rather than reticulated. The median portion of the wing is imperfectly reticulated. The terminal margin and the unicolorous fringe are conspicuously marked with a black spot on each vein.

Secondaries thinly clothed with fuscous hairs, permitting the reticulations of the lower surface to be seen in transparency, except between the margin and costal nerve, where it is seated in pale ash, as the primaries. Terminal margin and the pale fringe, black spotted as the primaries.—(Lintner, Ent. Contributions, iv, 130, 1878.)

7. THE TOOTHED-LEGGED BUPRESTIS.

Chrysobothris dentipes Germar.

Order COLEOPTERA; Family BUPRESTIDZ&.

Fic. 15.—Chrysobothris dentipes: a, head, front view; 0, last male ventral segment; c, last female ventral segment; d, first leg of male. After Horn. B. The same, after Smith.

Eating a slender, winding, broad, shallow burrow between the bark and sap- wood of newly felled oak trees; a white, footless grub, with the fore part of the body enor- mously large, circular, and flattened, inclosing the small head in front.

This singularly shaped borer is often found under the bark of newly felled oaks, or those which have been prostrate for a longer time. We have found it in its mine under the bark of the red oak at Salem, Mass., early in May, in company with more numerous individuals of Magdalis olyra.

OAK-BORERS. 61

It will be seen by the form of this singular borer that it is adapted for a life under or next to the bark of diseased trees, as it is quite unfitted, by reason of the enormously swollen front rings of the body, for boring very far into the living fresh wood, as is the case with the oak-boring eat- erpillar of Prionoxystus robinie, or the oak pruner (Hlaphidion villosum), With its short, powerful jaws it can eat its way on either side in front of it, after hatching from the egg, which is probably laid by the parent beetle in some crack in the bark. Its head is rather small and partly sunken within the segment next behind the head. This segment, des- tined to be the prothorax of the beetle, is remarkably broad, nearly three times as much so as the hinder segments, and fully as broad again as it is long, while the surface above is flat and more or less rough or pitted in the middle. With this unusual form it can eat its way in a Serpentine course under the bark, deriving its nourishment from the sap-wood next to the bark. Owing to the form of its body in front, the burrow is shallow and broad, in transverse outline oval cylindrical. The body of this as well as most other borers is provided with fine, _ delicate, scattered hairs, projecting on each side of each segment. Judging by analogy, these hairs are probably provided each with a fine nerve (though this remains to be proved), and probably are endowed with a delicate sense of touch, useful to the insect as it moves to and fro in its gallery. The Buprestid larve are blind, without simple eyes, since living as they do in total darkness and never coming to the light they do not need even the simple eyes present in many other larve, and which are probably chiefly of use in enabling the insect to distin- tinguish light from darkness.

The larve of the Buprestide and the breeding habits of the beetles have not as yet been carefully studied in America, and for any exact knowledge we have to go to French and German authors.

According to Perris, the Buprestids couple in the usual manner, the male mounting upon the back of the female, the act of copulation not being of long duration.

The form of the eggs and their size in our species are unknown, or have not been stated in print. It is most probable that the female lays them in the bottom of cracks in the bark, or under the partly loosened bark at least, where the larva upon hatching may find itself next to or im- mediately in contact with the bast or the sap-wood, which probably forms the greater part of its food, though Ratzeburg has found that the “frass” or excrement is colored by the bark, which indicates that the larve feed both on the bast and bark. As to the number of eggs laid by the female we have no information. The eggs are deposited in fissures or cracks by means of the extensile end of the body. As Westwood states, ‘‘The abdomen appears to be composed of only five segments; the remainder are, however, internal, and constitute in the female a retractile, corneous, conical plate, employed for depositing theeggs in the chinks of the bark of trees within which the larve feed.” Perris, however, says that “the

62 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

eggs are deposited in the interior of the bark, the outer layers of which the ovipositor of the female penetrates.”

It has been claimed by Ratzeburg and also by Reifsig* that the European larve of Buprestis and the numerous allied genera, such as. Chrysobothris, Chalcophora, etc., attain their full size in two years ; but according to Perris the time required for their transformations is but a. single year, as may be seen by the extracts from his work further on.

As regards the habits of the larve we have no direct observations on the young of this family in this country, though much needed in con- nection with the use of remedial measures.

Mr. E. Perris, in his invaluable work, entitled “‘ Insectes du Pin mari- time,” says of the larva of the European Ancylocheira flavomaculata :

The larva of the A. flavomaculata lives in the wood of old pines recently dead, and especially in the larger branches and the large twigs (pieux). It is, indeed, under these two last conditions that they oftenest occur. It does not stop in the bark, because it. is in the interior of the bark that the female lays its eggs, by means of its oviduct, and after its birth it plunges into the wood to the depth of about a centimeter [nearly two-fifths of an inch]. It follows the longitudinal fibers of the sap-wood while mak- ing a gallery elliptical in section, which it leaves behind it completely filled and packed with excrement and detritus. When the time of its metamorphosis approaches it. goes towards the surface of the sap-wood, perforatesit to the bark, sometimes makes. a small incision into the latter, stops up the gallery with a plug made entirely of small, compacted chips; then it retires backward a little into a cell scooped out in the wood, and this is where it transforms into a pupa.

The following extract from Perris refers to the habits of Chrysobothris solieri, which also lives in the maritime pine in France. The habits of our C. dentipes of the oak, and C. femorata of the oak and different fruit trees, and (@. harrisii of the white pine are probably quite similar.

According to my observations the Chrysobothris only lays its eggs on the trunks of pines from five to fifteen centimeters in diameter at the base, and on the branches of old trees. I have never found it on an old trunk, and when a large prostrate pine is deprived of its branches it is on them that it lives, and not on the trunk. I have already said that the larva lives at first under the bark; it there busies itself, some- times attacking very plainly the sap-wood, sometimes boring a sinuous gallery, which it leaves behind it filled with white chips and excrements of a brownish red; but at the approach of winter it burrows into the wood, where it gouges out a gallery ellip- tical in section, the dimensions of which increase as its body grows larger. When the moment of transformation has arrived it returns into its gallery, and undergoes its metamorphosis sometimes more than two centimeters from the surface, because I have found some pup and perfect insects at this depth.

Perris calls attention to the fact that though the Buprestid beetles. stand quite high in the Coleopterous series, yet their larve have an organization inferior to that of all other Coleopterous larve known. Thus, they have neither feet nor eyes, and there are no other Coleopte- rous larve which, as in the Buprestids, have very rudimentary labial palpi, and which consist of less than two joints.

*Ratzeburg’s Die Waldverderbniss, etc., ii, p. 360.

OAK-BORERS. 63

The burrows of the Buprestid larve may nearly always be distin- guished, says Perris, by their tortuous course. and by the fact that the excrement and detritus, instead of being accumulated in the gallery without order, are there disposed in small layers forming concentric ares, whose opening is turned away from the larve, and of a regularity not less remarkable than characteristic.

This symmetrical arrangement has as its primary cause the dimensions of the gal- lery, which are out of proportion with the abdomen ofthe larva. The latter, because of the size of the anterior portion of its body, is obliged to give to its gallery a size sufficient for the posterior part to execute freely movements of advance and retreat, which have as their natural result the disposition en arc of the rejected material be- hind. On the other hand, the larva, in consequence of the dimensions of its gallery, in order to have points of support is obliged to bend the posterior part of the body on itself. It is, indeed, ordinarily found in this attitude, which allows it to press against the walls, so as to push itself ahead; but in thiscondition the abdomen forms an are which, propping itself from the convex side on the detritus, causes the concay- ity of the successive beds. * * * :

We have seen that some Buprestid larve undergo their metamorphoses in the inte- rior of the bark, others in the thickness of the wood. It is, moreover, in this that the wisdom of nature is revealed, for itis not capriciously and without motive that things happen as I have described. We know, indeed, that if those larve which do not at- tack the young trees, as those of Ancylocheira 8-guttata, of Chysobothris solieri, and of Anthaxia morio, and of several species of Agrilus, should live under the bark they would not be sufficiently protected, because the bark is not thick enough and would easily separate from the wood. When, however, on the contrary, they live under the hard and thick bark of old trees, as Melanophila tarda, Chrysobothris affinis, Agrilus biguttatus, and 4-guttatus, and others, they do not hesitate to take refuge in the bark, because they are there well sheltered, and because they save the beetle from making a long and difficult journey in order to make its exit. * * *

What is the duration of the life of the larve of the Buprestide? Ratzeburg is inclined to believe that it is two years. M. Levaillant, whose observations are repro- duced by M. Lucas in his notice of Chalcophora, is also disposed to think that those of this insect pass two years in the wood. The reason which he gives, and which is drawn from the size of the larve found from December to August, does not seem to me conclusive, because the female of Chalcophora is capable of laying eggs during almost the entire year. Asto M. Ratzeburg, he has not, apparently, made careful observations in this respect.

As to myself, numerous facts authorize me to say that, in general, these larve only liveone year. For example, some pines, poplars, and willows which I have cut down in the spring time, with the design of obtaining Buprestids, have afforded me often very numerous perfect insects in May and June of the year following.

Some logs of oak, cut in January, 1847, and which lay during a whole year in the open air, furnished me in June and July, 1848, more than three hundred Chrysobothris afinis. The trunks of some large, very rigorous pines, cut down at the beginning of one year, contained pup: of Ancylocheira in the following May. Finally, as regards all the species that I have here described, and for a number of others, I have, from my own experience, the certainty that the larve live only one year.

I admit that, without doubt, among theselarve there are some which, not placed in conditions sufficiently favorable to complete during this period all the phases of their existence, from one cause or another, may be retarded some months, for a year even. Imoreover accept the more willingly this fact, because I have had good occasions for observing this in larvee which I have raised in my cabinet; but this isthe exception,

and the rule is that a single year sutfices, in our country, for the development of the larve of the Buprestidz,

64 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

The Buprestids in the perfect state love the daylight and sunshine. Before storms, when the air is calm and heavy and the sun is hot, they have an extraordinary activity; and when the weather gradually becomes cloudy and the wind rises they disappear from our sight. We know but little as to the nature of theirfood. Chalcophora ma- riana devours the young shoots of pines, Anthaxia morio and chevrierii eat, the first the petals of buttercups, the second those of Cissus alyssoides. Other Anthaxie also, as well as Trachys, frequent different flowers. Aphanisticus emarginatus occurs on rushes (joncs), and I have sometimes taken Acmeodera teniata on the flowers of carrots. All these facts lead me to think that the» Buprestids are phytophagous; but it appears that certain species are, accidentally at least, carnivorous. This ap- pears from a communication made by M. Léon Fairmaire to the Société Entom- ologique, in its session of January 10, 1849, relative to the subject of Chrysobothris solieri.

Regarding our oak-borer (C. dentipes), Harris states that it completes its transformations and comes out of the trees between the end of May and the first of July. This applies to Maine and Massachusetts. In New York, according to Dr. Fitch, the beetles are ‘‘often found bask- ing in the sunshine on the bark of the trees in June and July.”

The beetle.—This insect is so named from the little tooth on the under side of the thick forelegs. Itis oblong, oval, and flattened, of a bronzed brownish or purplish- black color above, copper-colored beneath, and rough-like shagreen, with numerous punctures; the thorax is not so wide as the hinder part of the body; its hinder mar- gin is hollowed on both sides to receive the rounded base of each wing-cover, and there are two smooth elevated lines on the middle; on each wing-cover there are three irregular, smooth, elevated lines, which are divided and interrupted by large,

thickly punctured, impressed spots, two of which are oblique; the tips are rounded. Length from }to ;,4 of aninch. (Harris.)

7. THE FLAT-HEADED BORER.

Chrysobothris femorata Fabricius. Order COLEOPTERA; Family BUPRESTIDA.

Boring under the bark and in the sap-wood of the white oak, and in the Gulf States, the pin oak; a pale-yellow flat-headed grub, closely resembling the preceding species.

This pernicious borer of the apple tree, as stated both by Harris and Fitch, originally infested the white oak, but since the settlement of the country has abounded in the apple and sometimes in the peach, but may still be found to injure the white oak. Riley has also found it in the soft maple and weep- ing willow. Riley has reared this beetle from the oak, apple, mountain ash, box elder, peach, and pear, and has found the larva in the mountain ash, linden, beech, cherry, and peach (7th Rt. Ins. Mo., 72).

Fig. 18 will fairly represent the ‘‘ mine” or gallery made under the bark of a stump Fic. 16.—Chrysobothris femorata: Of the white oak, as it occurred at Prov-

wed soot ventral ceuontor idence, R.I. The worm soon after hatch-

female; d, first leg of male.—

After Horn. ing made the mine as is seen on the right of

3 hk 3

_—_

OAK-BORERS. 65

the figure, where after a sinuous course it opens into a broad, shallow cell, and then after pursuing an irregular direction dilates on the left into a broad, shallow cell two-thirds of an inch wide; the oval, black spot in the upper corner representing the hole made by the larva for the exit of the beetle. In this hole the beetle was found. The large cell is for the repose of the pupa.

At Houston, Tex., I found the larva and pupa in abundance, April 2, 1881, under the bark of large pin oak stumps and of dead trees. The burrows were like those represented in Fig. 18, being irregular winding, shallow burrows, not nearly so definite in outline as those made by longicorn borers. The mine is about 2 inch wide, and terminates in a broad, irreg- ular, oval cell 14 inches long and 4 to 3 inch wide. In this cell the pupa spends the winter and early spring. One end of this cell lies toward the outer side of the bark so that even if there is not a clearly defined oval opening, as in Fig. 18, the beetle on emerging from the pupa state can with little difficulty extricate itself from its cell and makeits way out of doors by pushing aside a thin barrier of bark. In the case of one in the pin oak there was @ yo. 17—Transformation of quite irregular, oval cell built up by the larva GiTssoba ins nem eion aide between the wood and the bark, the partition OEE were, arom niles, consisting of a composition of firm bark dust, thus forming a rude cocoon. The insect occurred at Providence in the larva, pupa, and beetle states May 20, though the larve were the most abundant.

Harris says of it from his observations in eastern Massachusetts :

Its time of appearance is from the end of May to the middle of July, during which it may often be seen, in the middle of the day, resting upon or flying round the trunks of white-oak trees and recently-cut timber of the same kind of wood. I have re- peatedly taken it upon and under the bark of peach trees also. The grubs or larve bore into the trunks of these trees.

Mr. Ricksecker remarks that on the Pacific coast it ‘attacks young fruit trees that have been scorched by the sun, but its natural food is the oak, for I have seen dozens of them in the branches of a small live oak that had been cut down less than an hour.” (Ent. Amer., i, 97.)

The following extracts trom Dr. Fitch’s first report will further serve to characterize the habits and appearance of this formidable pest of our most valuable forest, shade, and fruit trees. It will appear that Dr. Fitch has been the first to discover an ichneumon parasite in the larva of this beetle, no European Buprestid beetle being, so far as we know, infested by internal parasites:

Another insect, which has not heretofore been noticed in our country as a borer in the apple tree, pertains to the family Buprestidae, or the brilliant snapping beetles. 5 ENT 5

66 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION.

Mr. P. Barry, of the Mount Hope nurseries, Rochester, has forwarded to us sections. of the body of some young apple trees, which were sent to him from a correspondent in Hillsborough, in southern Ohio, who states that in that vicinity the borer, which is contained in the specimens sent, is doing great damage to the apple trees, and that he has had peach trees also killed by this same worm. From an examination of these specimens, it appears that this insect is quite similar to the common apple-tree borer in its habits. The parent insect deposits its eggs on the bark, from which a worm hatches, which passes through the bark and during the first periods of its life consumes the soft sap-wood immediately under the bark. But*when the worm approaches ma- turity and has become stronger and more robust, it gnaws into the more solid heart- wood, forming a flattish, and not a cylindrical hole such as is formed by most other borers, the burrow which it excavates being twice as broad as it is high, the height measuring t .e tenth of an inch or slightly over. It is the latter part of summer when these worms thus sink themselves into the solid heart-wood of the tree, their burrow extending upwards from the spot under the bark where they had previously dwelt. On laying open