. 11 ill LIBRARY OF 1885-1056 .-f.oV TWENTY-THIRD REPORT STATE ENTOMOLOGIST Noxious and Beneficial Insects STATE OF ILLINOIS TWELFTH REPORT OF S. A. FORBES CHirAOO R. DONNELLKY & SONS CO. Printers 1905 CONTENTS. PAGK Introductory Note viii Tlie more Important Insect Injuries to Indian Corn 1 Divisions of the Corn Insect Group 2 Adaptations and Reactions of the Corn Plant to its Insect Visitants 3 General Effect of Insect Injury 5 General Measures of Prevention and Remedy. 6 Insect Injuries to Different Parts of the Corn Plant 6 Injuries to Corn by the Different Orders of Insects ?) Igg The Leaf-beetles (Chrysomelidce) jgg Melasoma lapponica (The Spotted Willow-beetle) 186 Luperodes varicornis , oy The Root-worm Beetles {Diahrotica) I87 The Flea-beetles {Halticini) Iqq Che ymorpha argus (The Argus Tortoise-beetle) ,[[[ 192 The Snout-beetles (Rhynchophora) 192 Otiorhynchus ovatus (The Strawberry Crown-girdler) 192 Limnoharis deplanata 1 qo Brachytarsus variegatus (The Corn-smut Beetle) I94 The Stink-bugs {Pentatomidce) I94 (Fbalus pugnax 104 Euschistus fissilis ,qc Euschistus servus , qc Euschistus variolarius iqc Thyanta custator I q^ Murgantia histrionica (The Harlequin Cabbage-bug) 196 Other Plant-feeding Jleteroptera I97 The Leaf-footed Plant-bugs (Leptoglossus) I97 Ligyrocoris sylvestris ig8 Sphragisticus nebulosus log Microtoma atrata iqo Calocoris rapidus (The Dusky Leaf-bug) I99 Pnecilocapsus lineatus (The Four-lined Leaf-bug) 200 Plagiognathus obscurus 201 Undetermined Leaf-bug (Capsidce) 202 Triphleps insidiosus (The Common Flower-bug) 202 The Flatas 202 Ormenis pruinosa (The Mealy Flata) 203 Chlorochara conica (The Green Flata) 203 The T;eaf-hoppers {Delphacinm and Jassidce) 204 Dia-anotropis sp 204 Liburnia ornata 204 Oncometopia undata 204 DrcEculacephala moUipes 205 Phlepsius irroratus 205 Gnathodus spp 206 Plant-lice {Aphididce) 206 Siphocoryne avenoe (The European Grain-louse) 206 Macrosiphum. granaria (The English Grain-louse) 206 Macrosiphum trifolii (The Clover Plant-louse) 208 Myzus achyrantes 209 Chaitophorus flavus (The Yellow Sorghum Plant-louse) 210 Diapheromera velii (The Prairie Walking-stick) 211 vu PAGE Grasshoppers {Acridida;) 212 Dichromorpha viridis (The Short-winged Green Grasshopper) 212 Boopedon nubilum 212 Dissosteira longipennis 213 Campylacanfha olivacea 213 The Cricket Family {Gryllidce) 213 Gryllus pennsylvanicus (The Pennsylvania Field-cricket) 214 Nemobius fasciahis (The Striped Cricket) 214 Tree-crickets — or White Crickets or Climbing Crickets — {(Ecanthina;) 215 Synoptical Key to Illinois Species 217 Notes on the Food of the White Crickets 218 OEcanthus angustipennis 220 (Ecanthus quadripunctatus 220 (Ecanthus nigricornis 221 (Ecanthus pini .■ 222 Thousand-legged Worms {Myriapoda) 222 Julus cceruleocinctus 223 Parajulus venustus 223 Parajuhis diversifrons 223 The Red Spiders (Tetramjchus) 223 Tetranychus bimaculatus 224 Tetranychus modestus 224 Key to the Discussion of Insect Injuries to Corn 225 General Grouping of Injuries to Com 225 A. Injuries to the Leaves 226 B. Injuries to the Stalk above Ground 226 C. Injuries to the Silks or to Kernels at the Tip of the Ear or beneath the Husks 226 D. Injuries to the Tassel 227 E. Injuries affecting the whole Plant 227 F. Injuries to the Underground Parts of the Plant: the Roots, the Planted Seed, or the Stalk near the Roots 227 The Leaf-eating Orthoptera of the Corn Field 229 Snout-beetles Injurious to Corn 229 Sod Web-worms Injurious to Corn 230 Insects eating Irregular Holes in the Leaves or notching the Edges 230 The Corn Cutworms 231 The Stalk-borers of Corn 232 Insects injuring the Corn Plant obscurely without Visible Destruction of any Part of it 233 A List of Corn Insects with References to Economic Vrticles: General Articles 234 List of Species 234 Hymenoptera ' 234 Diptera 235 Lepidoptera 236 Coleoptera 249 Hemiptera 261 Orthoptera 268 Myriapoda 272 Acarina 273 INTRODUCTORY NOTE. In the Eighteenth Report of the State Entomologist of IlHnois — the seventh of the present writer — was pubhshed the first part of a mono- graph of insect injuries to Indian corn, treating of injuries to the planted seed and to the roots. The present report is in continuation of the fore- going, and relates to injuries to those parts of the corn plant which are exposed above ground. Both divisions of this text have been made to include a discussion of more than the strictly injurious species, this second part especially giving practically eqvial attention to the corn insects generally, whether of present economic importance or not. I have, however, divided them into "the more important," "the less important," and "the unimportant" species, and have treated those notably injurious in a strictly practical manner with a minimum of technical discvission. In preparing this paper for publication I have of course drawn freely on all sources of information known to me, but owing to the large number of species included it has been impossible to give in so brief and comprehensive a paper my authorities in detail, or even to distinguish new matter from old, or contributions of this office from those made by numerous other workers in this field. I have, however, compensated for this deficiency as well as I could by printing a list of the species discussed, with fairly full bibliographical references to the economic literature of each. I am under unusual obligations to Mr. C. A. Hart for aid in the col- lation and organization of the material for this report and in the prepara- tion of manuscript, especially that on the more technical parts of the subject. Most of the figures originating in this office — several of which are here printed for the first time — are from drawings made by Mrs. L. M. (Hart) Green; and the responsibility of seeing the report through the press has fallen mainly upon Miss M. J. Snyder, for many years Secretary of the State Laboratory of Natural History and proof-reader in my entomological office. I am indebted for many of the illustrations here used to Dr. L. 0. Howard, Professor F. L. Washburn, Mr. Wm. Beutenmiiller, Professor M. V. Slingerland, Dr. A. T. Neale, Professor John B. Smith, Director C. E. Thome, and Dr. W. E. Britton. S. A. FORBES, Illinois State Entomologist. A MONOGRAPH OF Insect Injuries to Indian Corn PART II THE MORE IMPORTANT INSECT IN- JURIES TO INDIAN CORN. The Illinois State Entomologist is by law required to investigate " the entomology of Illinois," and particularly to study " the history of the insects injurious to the products of the horticulturists and agricul- turists of the state," and to prepare " reports of his researches and dis- coveries in entomology for publication by the state." While the main end of his studies should thus be economic, the whole subject of the entomology of Illinois is nevertheless open to his investigation and report. The advancement of entomology as a science and the adap- tation of entomological knowledge to educational uses, if not his duty, are clearly within the general field of his privilege. I have accordingly, in the preparation of this report taken into especial account the rapidly rising interest in nature study as a useful feature of the work of the elementary school, and I have availed myself of the opportunity to incorporate into the present discussion much matter of little or no economic interest, but worthy of presentation, nevertheless, as material of value to the public school teacher in search of information concerning the commoner objects of his neighborhood. The corn plant is so conspicuous a feature in the agriculture, and hence in the civilization, of Illinois that it must always be an attractive subject of study to the youth of the state, and suitable in a multitude of cases for use in the public schools. Like most of the larger and more abundant plants, it draws to itself a considerable assemblage of insects which find in it various attractions and advantages contributing to their maintenance or their pleasure, and which thus, by their common interest in this one great plant, come to form a kind of associate group, the group of the corn insects. Very few of them are peculiar to the corn plant alone, since nearly all of them are equally or even more strongly attracted to other plants as well. Many of them, indeed, belong to a considerable number of such plant-insect groups, visiting or living on many other plant species, cultivated and wild. Not one of them is immediately beneficial to the corn plant itself. although a considerable number, parasitic or predaceous on other in- sects, are indirectly beneficial to it by relieving it to some extent from the attacks of insect enemies. Several of them do no appreciable harm at any time; others are injurious only uijder special conditions more or less rare; and still others are injurious to it whenever and wherever they occur. , Their common interest in this one plant of course brings these insects also into important relations to each other, like those which influence any local assemblage of animals — those of a pond, of a grove, or of a barnyard, for example — and make of them a related group in- stead of a mutually indifferent assemblage. It is the object of the present report to discuss this entire group of corn insects, to the end that the teacher and student, of whatever grade, may find in this paper a clue to the whole system of insect life of which the corn plant is the center. The study here presented may thus stand as in many respects a type or example of the relations of a plant to its insect visitants. While in this treatment the economic features of the system will receive full attention, this will not be to the exclusion of features of scientific or educational interest merely ; but to avoid encum- bering the more important economic matter wdth details and discussions of secondary interest, the paper is divided into sections, based on the economic relation. Divisions of the Corn Insect Group. The entire assemblage of corn insects is much too large and compli- cated for convenient discussion as a whole, and it may consequently best be divided into subordinate groups, some corresponding to the different organs and structures of the corn plant itself, others to different stages of its growth, and still others to the previous history of the land on which the corn is grown or to the situation of the field with respect to other and adjacent crops. There is, for example, a small group of insects which become abundant in corn fields only where corn is grown on the same ground year after year — the corn root-worm is an instance — while others, like the wireworms, infest corn injuriously only w^hen this follows within a year or two upon grass, and others, like the stalk-borer, may invade corn only from grass-lands outside. The corn root-aphis makes its main attack on the crop while the plant is young, and the leaf-aphis usually does not appear until the crop is well advanced, and continues in rapidly increasing numbers until frosty weather checks its multiplication. Among the groups corresponding to the different parts and organs of the growing plant the most definite distinction is between those especially adapted to a life under ground, and those which never enter the earth in search of food. The white-grubs, wireworms, corn root-worms, seed- corn maggots, and root-lice are on one side of this dividing line, and the chinch-bug, army-worm, corn-worm, leaf-louse, and a host of additional species are on the other. Among the subterranean corn insects we may distinguish a few which feed only on the softened seed in the earth; others confined to the living roots; other root insects which may extend their injuries to the underground part of the stalk; and still others which may also eat the seed. While the relations of the injurious species of corn insects to the plant thus differ widely, making it possible to divide the species accord- ing to these relations, groups so formed are by no means as definite and sharply limited as those in a classification based on form and structure, but they overlap and intermingle variously, and may even undergo radical change with the lapse of time — a change corresponding to a change of habit in a species with the changing conditions around it. This is merely saying in other words that the actions, behavior, habits, and preferences of insects are more flexible and variable and far more readily adaptable than such of their structures as are used in their classification. Adaptations and Reactions of the Corn Plant to its Insect Visit.^nts. There is little in the structure or the life history of the corn plant to suggest any special adaptation to its insect visitants — no lure to insects capable of service to it, or special apparatus of defense against those especially liable to injure it. The fertilization of its seed is fully pro- vided for without reference to the agency of insects, and would be as well accomplished if none of them ever carried pollen from the tassel of one plant to the silk of another. Hence the plant secretes no honey and has no floral odor or colored bloom. It has no armature of spines or bristly hairs to embarrass the movements of insects over its surface or to defend against their attack the softer and more succulent foliage at its growing tip. It secretes no viscid fluids to entangle them, and forms no chemical poisons or distasteful compounds in its tissues to destroy or repel them. The cuticle of its leaf is neither hardened nor thickened by special deposits; its anthers are neither protected nor concealed; and its delicate styles — the silks at the tip of the ear — are as fully exposed as if they were the least essential of its organs. Minute sucking insects are able at all times to pierce its roots and its leaves with their flexible beaks, and with the single exception of its fruit there is no part of it which is not freely accessible at any time to any hungry enemy. Only the kernel, which was lightly covered in the wild corn plant by a single chaffy scale or glume, has become, in the long course of development, securely inclosed beneath a thick coat of husks, impenetrable by nearly all insects; and we may perhaps reasonably infer that among the possible injuries against which this conspicuoas protective structure defends the soft young kernel those of insects are to be taken into account There are also, of course, many insect species, even among those which habitually frequent the plant, which are unable to appropriate certain parts of its substance to their use, but this is because of the absence ot adaptation on their part and not because of any special defensive adaptation on the side of the plant. The adult or beetle of the com ^oot-worm (Diahrotica longicornis) is an example. The larva of this insect feeds only on the roots of corn, and the beetles consequently all make their first appearance for the year in corn fields, and find their food at first on the corn plant. Owing, however, to the weakness of their jaws they are unable to eat the leaves of corn, and feed only on the fallen pollen and the young silks just growing out from the husks. Later, as the pollen disappears and the silk dries up, they are driven to other plants, or even compelled to leave the field entirely in search of food, and hence are found at that time on clover heads afid on the flowers of thistles and ragweed and other late-blooming plants. Thus we may say that with the exception of the ear the whole plant lies open and free to insect depredation, and that it is able to maintain itself in the midst of its entomological dependents only by virtue of its unusual power of vigorous, rapid, and superabundant growth. Like every other plant which is normally subject to a regular drain upon its substance from insect injury, it must grow a surplus necessary for no other purpose than to appease its enemies; and this, in a favorable season, the corn plant does with an energetic profusion unexampled among our cultivated plants. Insects, indeed, grow rapidly as a rule, but soon reach their full size. Many species multiply with great rapidity, but even these the corn plant will outgrow, if given a fair chance, provided they are limited to corn itself for food. The great injuries to corn by insects are done by species which come into it from other and earlier crops; insects which are in the full tide of their multiplication, or perhaps at their maximum number for the season, while the corn plant is still small and young. It is not the corn root- aphis which injures corn most seriously, although confined to the corn plant and endowed with a power of multiplication scarcely surpassed among insects ; it is the chinch-bug, which breaks into the field of young corn from adjoining wheat or oats, where it has already increased a hundred-fold since spring began ; it is the army- worm or the cutworms, or the wire worms, or the white-grubs, which began and got most of their growth in grass, and now, by their numbers and voracity, overwhelm the young corn before the time of its most rapid growth has arrived. Practically limited to this vigor of growth as a means of escape from insect attack, an5dihing which checks or retards its growth for a consid- erable time has, of course, the effect to increase insect injury. Thus, a cold and backward spring after corn-planting increases injury to the seed and the young plant by wireworms, seed-corn maggots, and the corn root-aphis; and a midsummer drouth greatly increases the effect, if not the amount, of injury by chinch-bugs, white-grubs, and the corn root- worm. General Effects of Insect Injury. With few exceptions, the effects of injury to corn by insects, where they do not amount to a total destruction of the plant, may be compared to the effects of simple starvation. Anything which lessens the store of food laid up in the corn kernel for use in germination and early growth, or damages seriously the roots or the leaves, or draws away the sap before it has served its purpose in the plant, practically amounts to a diminution of the available food supply. An impoverished soil, very dry weather, the sapping of the cells and vessels of the plant by sucking insects, destruction of any considerable part of its roots, and the dead- ening or destruction of any large percentage of its leafage, all have similar consequences, which may be classed as starvation effects, and when two or more of them coincide, each serves, of course, to intensify the effects of the others. One common result of these starvation injuries to corn is the failure of the plant to form the ear; the stalk itself, perhaps, making a fairly vigorous growth, but remaining barren, and hence useless except for fodder. Injury to the roots, if continuous and severe, has, however, another effect, of a more special character, in so weakening the hold of the plant on the earth that the stalk readily falls after it has become top- heavy with growth, and is not able to rise again. This happens after soaking rains have softened the ground, especially if accompanied by heavy winds. It is sometimes a consequence of the destruction of the roots by the corn root- worm and the white-grubs, and is sometimes due to chinch-bugs, which, by sucking the sap from the base of the stem, prevent the formation of the strong ".brace-roots " — the upper circle of roots — put forth during the last stages of the growth of the stalk. Actual loss of roots sometimes also delays the development of the plant, acting in this respect like an unusually cool summer. Thus, a field infested by grubs or root-worms may remain green after unin- jured fields are practically ripe. Such backward fields are especially exposed to injury by frosts, and hence are likely to yield an unusual amount of soft corn. Besides this class of general injuries, which diminish the vitality and lessen the size or delay the growth of the whole plant, there remain only the more local injury to the ear, caused almost wholly by the caterpillar known as the corn root-worm, and the damage clone to the ear in the crib or to the kernel in the bin by the weevils and other insects of similar habit. With respect to their economic mischief, there is probably little to choose between those insects which, by destroying or weakening the plant, prevent the development of the ear or diminish its size and those which destroy the mature product. One deprives the farmer of the reward of his labors and investments as completely as the other. General Measures of Prevention and Remedy. From what has been said above with respect to the starvation effect of most insect injuries it follows that any management which helps to maintain and strengthen the plant by furnishing it better or more abun- dant food will lessen, or perhaps wholly prevent, losses from insect injury which must otherwise be serious or complete. A strong, rich soil, well cultivated, well watered, and well drained, may grow a good crop not- withstanding an amount of infestation by chinch-bugs, root-lice, root- worms, and white-grubs which would be fatal on poor or poorly managed land. The good corn farmer may thus escape with a profitable yield under insect attacks which will leave his less intelligent or less careful brother in debt after his crop is harvested. This is not merely because the vigorous plant will easily support an amount of injury under which the unthrifty one will suffer or succumb. It is an established fact that many insects themselves will not thrive as well or multiply as rapidly on a vigorous, quickly growing plant as on one in feeble condition. More special measures are a proper rotation of crops, such that corn shall not be exposed to injury by insects which have bred on the same ground the preceding year, either in other crops or in corn itself; timely plowing, to forestall the breeding of insects by destroying them or their food; timely planting, with reference to the period of the* greatest abun- dance or greatest activity of certain species; and the use of barriers against the movement of certain destructive species into the corn from fields adjacent, combined with insecticide measures against hordes or companies of destructive insects, which if left to themselves will work great and immediate harm. » Insect Injuries to Different Parts of the Corn Plant. To the Leaves. — That the abundant, conspicuous, and easily accessible foliage of the corn plant should attract a large number of hungry insects and suffer more from their attentions than any other part, is naturally to be expected, since, as a consequence of its gradual and long-continued growth, it offers for consumption during many months the most succu- lent and nourishing food which the plant produces. More than one hundred species of insects, representing all of the orders injurious to corn, have, in fact, been found feeding on the leaves. The most important differences in their injuries are due to differences in the mouth-parts of the insects — whether sucking or biting — and the principal differences subordinate to these are due to differences in size, number, and feedin^ Fig. 5. The Variegated Cutworm (Peridroma maroiiritosa sauna): a, adult; 6, c, f/, larvcE; r, /, eg!;s. I- igure « greatly enlarged; others natural size. (Howard, U. S. Dept. of Agriculture.) 2i ground-color of the back. The freshly hatched caterpillars are greenish. with black heads. This is a very common species, but is peculiar in its habits. It climbs plants freely at night to feed, even ascending bushes and fruit-trees, and devouring any succulent tissue which it finds, including bud, fruit, flower, leaf, stalk, and root of the plant. It occurs frequently in corn fields, although not ordinarily common there. When very abimdant it sometimes migrates in hordes like the army-worm, in search of food, and under such circumstances has been known to destroy hundreds of acres of young corn in a comparatively short time. It is pre-eminently a garden pest, however, being particularly destructive to fruits, vegetables, and flowers rather than to grain, crops, weeds, and wild plants. A remarkable outbreak of this cutworm oc- curred in the year 1900 in the United States and Canada, especially in the states of the Pacific coast. Enormous damage was done by it, particularly to fruit and vegetable Wx/viy-i^TI. crops. A full account of this occurrence \-^^^^ will be found in Bulletin 29, N. S., U. S. Division of Entomology, and in Bulletin 47 of the Experiment Station of Washington state. Among its leading food plants are cabbage, tomatoes, potatoes, clover, onions, peas, beets, and carnations. It occurs throughout nearly the whole of the New World, and also in western and southern Europe, northern Africa, and Asia Minor. The seasonal history of this species is not yet well understood. It has been seen in winter as larva, as pupa, and as adult, and entomolo- gists differ, consequently, in their statements«as to its normal hibernating stage and the number of its broods. It agrees with most of the species, however, in the fact that it is destructively active in early spring, becom- ing most injurious in May and early June, pupating in June, and begin- ning to produce moths (Fig. 5, a) abundantly in the latter part of that month. The data which we have suggest at least two broods in a year, but there is nothing conclusive upon that point. Eggs (Fig. 5, e, f) of this species were sent to us March 27 on an apple twig from Vandalia, and others were sent us April 17 from Hardin county, in southern Illi- nois, which were just hatching when received. The young cutworms were kept on clover until May 26 by which time they had reached an Fig. 6. The Variegated Cut. worm {Peridroma margaritosa soMcio), back and side views. En- larged. average length of about one inch, being, in other words, at this date some- what more than half grown. Female moths, on the other hand, confined in a breeding-cage with blue-grass July 10, had given origin six days later to freshly hatched larvse, with which the cage was swarming at the time. Unfortunately, these presently died — probably because the food plant offered them was unsuitable. Other entomologists have several times secured and hatched the eggs of this species in the latter half of the season. In 1900, cutworms of this species — probably of the second brood — began to appear early in July, reached their greatest abundance about July 25, and had disappeared by the end of the following month. The advent of winter commonly finds individuals in every stage of growth, and moths, larvse, and doubtless pupae also may pass the winter successfully. We once found four larva in early December under boards and weeds in grass and corn. Two of these were about a third of an inch in length, and the others were approximately an inch and a quarter. Two full-grown larvse were also found January 14 and 24. Fortunately, this cutworm is not ordinarily sufficiently injurious in corn fields to require special precautions except when it moves in com- panies from its breeding grounds, and then it may be dealt with like the army-worm, by measures to be described in the article on that species. The Spotted Cutworm. Noctua c-nigrum Linn. The spotted cutworm is a common species, injurious in Europe as well as in America, especially to garden vege- tables, which it seems to prefer to grasvses and grains. It has occasionally injured Indian corn in various states, and, like the species just discussed, is liable to travel in companies when it becomes very numerous. Under these circumstances it might require the especial attention of the corn grower. It is on record also as injuring wheat in January and in March. (Webster.) It may be recognized (Fig. 7) by two rows of triangular black spots, one on each side of the back, with the narrow angle to the front, largest and darkest on the posterior seg- ments of the body, and fading out before they reach the head. The general color of the cat- erpillar is pale brownish or ashy gray, and it is fig. 7. The Spotted Cutworm about an inch and a half long when of full size. views"" Enlarged.' It hibernates as a cutworm nearly full grown, and pupates quite early, in central Illinois late in April and early in May: conse- m vfcd 26 Fig. 8. The Spotted Cutworm (Noctua c-nigrum), adult. Natural size. quently, if injuries to corn are due to this species they will soon cease, and the first replanting will commonly escape unharmed. Moths (Fig. 8) from pupse formed in April and early May have ap- peared in our breeding experiments during the latter part of May and the first half of June, and, proceeding without much delay to deposit their eggs, they gave origin to a second brood of cutworms which be- came fairly well grown about the middle of July. This generation is not often found in the corn field, and does no injury there worth noticing. The moths from this sec- ond brood have appeared in our breed- ing-cages from late July to the middle of August. They continue alive in the fields throughout September, and lay their eggs in grass for the hiber- nating brood of the cutworms. Early fall plowing of infested grass-lands may thus be expected to take effect on this cutworm by pre- venting the laying of many of the eggs, and by causing the starvation of many of the young which may already have hatched. The Dingy Cutworm. Feltia suhgothica Haw. The Western Striped Cutworm. Feltia jaculifera Guen. (Agrotis tricosa, A. herilis.\ The dingy and the striped cutworms are remarkably alike in both appearance and habits, and may well be treated together. The former (Fig. 9) is dingy gray, and easily recognized by the dusky band on each side of the back, obliquely notched on the inner border like the edge of a serrated leaf. The broad dorsal space between these bands is a buffy gray. There are also a well-marked light band along each side of the body, and dorsal and lateral pale lines rather feebly marked. The western striped cutworm is very closely similar to the preceding, perhaps indistin- guishable in tlie caterpillar stage. Riley says, indeed, that it is more dingy than suh- gothica, with less conspicuous lines, and with a more decided buff tint to the dorsal band. These differences are, however, within the range of ordinary variation, and the species fig 9 The pingy cutworm can apparently be distinguished with cer- Sfi^ewf ^ESged^"'' '"' tainty only by breeding to the adult. The young larvse are much darker at first, sometimes nearly black. The dingy cutworm is one of the commonest species, especially in corn, where it shares with the greasy cutworm the principal injury to that crop. Indeed, there is some reason to believe that the moth may lay her eggs in fall among the succulent weeds in the corn field, particu- larly when a severe drouth has made the pasture and meadow lands less inviting. In accordance with this supposition these cutworms have not infrequently been found in early spring generally distributed through corn on old corn ground. Stedman speaks of it in Missouri as the most destructive cutworm in wheat. In our breeding-cages it has evidently preferred clover to blue-grass. It is especially fond of early vegetables, including melons, cabbage, tomatoes, beans, peas, sweet potatoes, tur- nips, lettuce, celery, and strawberry plants. It occasionally climbs fruit- trees and shrubs to devour their buds and leaves. The striped cutworm is also decidedly destructive to corn, according to Webster, one field in Indiana being completely ruined by it in 1895. Similar injuries were noticed in the same year in Missouri, Kentucky, Tennessee, and southern Ohio. It was the most abundant cutworm in southern Illinois in the outbreak of 1887, and, next to gladiaria, the com- monest and most destructive throughout the state during that of 1888. It did much harm to corn in these years, but was especially injurious to clover, for which it had an evident preference, and to the meadow grasses. It frequently migrates when abundant in search of food, but without the concerted movement of the true army-worm. Both of these species are generally distributed throughout the United States and Canada east of the Rocky Mountains. The dingy cutworm is also found on the Pacific coast, and we have specimens of the moth from Montana, Wyoming, and Utah. The striped species occurs in British Columbia. There is but one brood of the dingy cutworm each year. Moths have been taken throughout July, August, and September, but much the most abundantly in the latter part of August. Eggs are quickly depos- ited, and hatch in about a week. The caterpillars grow slowly, and hibernate when c[uite small. Those taken by us in January, February, and March averaged less than half an inch in length, but when warm weather comes they grow apace, and in May become nearly full grown. In June they cease feeding, mostly in the first half of the month and enter the ground for pupation. A dingy cutworm kept under observa- tion in my insectary from May 15 entered the ground June 16, and continued as a larva in its earthen cell until August. On the 12th of this month it was found to have changed to the pupa, and on the 28th it became an adult. This long-delayed pupation was not due to drouth, as the earth in the breeding-cage was kept moist, and even wet. Besides 28 the above we have found larvae of different lots in a similar condition in our breeding-cages June 15, July 2, 19, and 23, and August 3. These facts indicate an unusuall}^ long period of midsummer preparation for the pupal transformation. This life history suggests nothing exceptional by way of prevention or remedy. Where the field has become infested in fall, as shown by the general distribution of the cutworms in the corn in early spring, replant- ing, to be safe, should be postponed until towards the middle of June. The Clay-backed Cutworm. Feltia gladiaria Morr. This cutworm (Fig. 10) is usually dark in average color, varying, however, from greenish gray to dark brown. The back is commonly decidedly light, grayish white or straw-color, or occa- sionally reddish brown. This light dorsal space is divided lengthwise by a more or less conspicuous median white line, which is usually bordered with darker. On each side of the pale dorsal space are two irregular whitish lines. The full-grown larva is about an inch and a quarter in length. This species is extremely variable in numbers, multi- plying under some conditions to become a notable and widely destructive pest, and then occurring in scarcely noticeable numbers for some years thereafter. It was not distinguished as a cutworm until 1888, when it was bred to the adult in our insectary. In 1887 and 1888 it was the most destructive cutworm in Illinois, especially to clover and yoimg corn. In 1895 it was by far the leading species in a general cutworm outbreak in Ken- tucky, and caused serious injury to a thirty-acre field of young corn on old sod ground near Champaign. In 1901 it was one of the most abundant cutworms in corn fields in western Illinois, and was excessively abundant in pansy beds at Urbana, cutting off and destroying all the plants. During its years of greatest abun- dance here it was especially notorious for its injuries to clover, which it preferred to blue-grass. It likewise ate oats, grass, and corn, invading com fields from adjacent meadows, and devouring the plants as it went as thorough- , , ,, Fig. 11. The Clay-backed Cutworm {Feltia gladi- ly as does the army-worm. ana), adult. Enlarged. Fig. 10. The Clay-backed Cut- worm {Feltia gladiaria). En- larged 29 It fed likewise on potatoes, beans, sweet potatoes, cabbage, tomatoes, and onions. When very abundant and their food supply had run short, these cutworms scattered in all directions — a habit common in varying degrees to most of the cutworms. Its mode of feeding is different from that of the cutworms generally, the corn leaf being seized by the hang- ing tip. drawn down, and eaten to the base. In clover fields, it begins at the tip of the plant and works downward, collecting about the roots. This species is registered as inhabiting the United States east of the Rocky Mountains, but we have specimens of the adult from Utah and Colorado also. It spends the winter, in our latitude, in the caterpillar stage, and is active in the destruction of its food plants from the middle of April to the beginning of June. By the middle of June all the cutworms have entered the earth for transformation. They do not change forthwith to the pupa stage, but remain there for a considerable period — more than six weeks in some cases — in a dormant or torpid condition. Moths (Fig. 11) consequently do not appear until September and early October, being most numerous in the latter half of September. Eggs are then laid without delay, and from these the larvae hatch, which pass the winter partly grown. It follows from this life history that the main measure for the protec- tion of corn against this cutworm must be an impassable furrow along the margin of the field next to grass or clover, or, in the absence of this, the distribution of poisoned food — clover particularly — where the cutworms are likely to be drawn to it. Owing to the lateness of the , period when the eggs are laid, a reasonably early fall-plowing will pre- vent the breeding of the species on that ground. The Bronze Cutworm. Nephelodes minians Guen. This is an unusually large and plump cutworm (Fig. 12) about an inch and three quarters in length, conspicuously marked with alternate stripes of olive-bronze and yellowish, the former much the broader. A pale stripe runs along the middle of the back, and there are two such on each side, the lower below the spiracles. The bronze space imme- diately above the last is frequently divided lengthwise by a delicate, broken yellow line. The head is yellowish or gray, the neck-shield darker, with five pale stripes. This is essentially a grass cutworm, being one of the commonest of its kind in grass-lands in early spring. It is somewhat injurious to corn, especially if this is planted on pasture or meadow lands occupied by it the preceding year. It eats clover sparingly or not at all, but seems to have a special preference for timothy. In the corn field it devours the whole plant insead of merely gnawing through the stem. It is not a garden species, although it sometimes climbs fruit-trees when its normal food is scarce, feeding on the buds and leaves like other so-called climbing cutworms. It is generally common and abundant throughout the United States and Canada- In Iowa it is regarded by Gillette as the most abundant species, next to the glassy cutworm, in fields of grass and corn. It did much injury to grass in New York in 1881, and worked unprecedented destruction in 1886 near Co- lumbus, Ohio, where, late in May, scarcely an acre of meadow or pastvire had a vestige of grass on it for a distance of several miles, many fields being dry enough to burn. About three thousand acres were thus destroyed, the larvae migrating en masse when their food was exhausted. Hibernating in our latitude in the larval stage, they are found active in grass-lands in April and throughout May. They begin to disappear about the 1st of June, and all are gone by about the middle of that month. They remain under ground for a considerable period without pupating, changing in late July and August. The moths (Fig. 13) first appear in early August, beome most abundant during the first half of September, and continue into October. The hibernating caterpillars have the singular habit of sometimes coming forth in winter and crawling about on the snow and ice. In the South, adults are frequently taken during the winter months. This cutworm is present in very unequal numbers year after year, what seems to be a bacterial disease checking its increase when it becomes unusually abundant. On this ac- Fir.. 13. The Bronze Cutworm (Nephelodes count, and also because much sub- minians), adult. Natural size. ject to insect parasitism, it is not likely to be excessively abundant in the same locality for two successive years. The facts concerning it suggest no special preventive or emedial measures other than those frequently referred to in this article. Where it is so abundant in grass-lands as to threaten a migratory movement, this may be arrested by measures usually applied against the army- worm. In case it scatters into corn from adjacent fields of grass, it may doubtless be killed by the use of poisoned food, particularly the mixture Fig. 12. The Bronze Cut worm {Nephelodes minians), back and side views. En- larged. of middlings aufl Paris green. In case corn is so injured by it as to require replanting, this may be safely done any time after the first of June, or possibly as early as the last week in May. To be sure that a grass sod shall be virtually free from the eggs, this should be plowed as early as the first week in September. Hadena lignicolor Guen. This cutworm closely resmebles the glassy cutworm, but has never been fully described in the caterpillar stage. We have not found it com- mon in Illinois, but have collected the moths during June, July, and August. Gillette reports that the moths are very common in Iowa, They are found generally in the northern part of the United States east of the Rocky Mountains, and have been reported from Arizona. A cutworm of this species which was found by Lintner preparing for pupation May 18, completed its transformations and came out as a moth on the 29th of June. Females dissected by Gillette July 13 were well filled with eggs. These facts indicate a comparatively early close of active life as a cutworm, and a comparatively early appearance of the adult moth. The W-marked Cutworm. Nodua dandestina Harr. This caterpillar (Fig. 14) is marked with four longitudinal rows of dark spots and some dark and pale longitudinal lines. The spots of the outer row on each side are oblique, and sometimes unite to form a continuous line; those on the inner row are more or less triangular Cmost evidently so on the hinder segments), and occa- sionally have the shape of the lett:r W. This is a very wide-spread species and a general feeder, but is ordinarily much more abundant in the East than in the north-central states. It is not found in the South. Dr. Lint- ner regards it as the most injurious corn cut- worm in New York, where it is said to be com- mon also on grass and grain, and to feed on buckwheat and clover. It is fond of garden vegetables, and feeds on lettuce, cabbage, celery, pumpkins, and beans. It is a well-known climlj- ing cutworm, ascendingt rees and shrubs to eat the buds and leaves, particularly those of the apple, box-elder, soft maple, currant, and gooseberry. Plantain is mentioned as one of its wild food-plants. Fig. 14. The W-marked Cutworm (Noctua dandestina), back and side views. Enlarged 32 The larvae winter over about half grown, and mature early, becoming most injurious in April and May. The moths begin to appear soon there- after, and are most abundant about June 20. The data on record indicate a probable second brood of the cutworms in midsummer, the moths appearing in August, September, and October. The early transformation of the hibernating brood renders precau- tions against this cutworm virtually unnecessary, since it can injure only very early plantings of corn. The Granulated Cutworm. Feltia annexa Tr. This species is best known by its rough, granulated skin, and by a pair of oblique marks on each segment, diverging backward. (Fig. 15, a, e.) It is a general feeder, devouring corn, wheat, and other cereals, cotton, clover, grass, cabbage, peas, beans, and several weeds. It is particularly well known in the Southern States as a cotton cutworm, sometimes so badly injuring this crop as to compel re- planting. It is not common in Illi- nois, but is found, neverthe- less, across the country from Massachusetts to California, and is abundant from Ken- tucky southward, and also in Cuba and South America. Lugger records a single cap- ture in Minnesota. The facts with regard to its seasonal history have not yet been clearly established. It seems to winter as a larva, and is most destructive in April and May. Moths (Fig. 15, h) of this brood appear in June, July, and August. From eggs laid August 3, moths were reared again by October. Beutenmiiller says a second brood flies in August, September, and October. There are almost certainly two generations in a year in Illinois, and quite likely three, or more, in the Gulf States. Fig. 15. The Granulated Cutworm (Feltia annexa); a, larva; b, its head, front view; c, d, one segment, top and side view; e, surface; /, pupa; g, tip of pupa; h, ad