\ BULLETIN OF THE ILLINOIS STATE LABORATORY OF NATURAL HISTORY LRBANA, ILLINOIS, e. S. A. VOL. VII. FEBRUARY, 1904 ARTICLES I. ~ lI. ART. 1. STUDIES OF THE LIFE HISTORY, HABITS, AND TAXO- NmIIC RELATIOKS OF A NEW SPECIES OF OBEREA \ OBEREA lJLMICOLA CHITTENDEN). ART. II. STUDIES OF THE HABITS AND DEVELOP.\IENT OF KEO­ CERATA RHODOPHAGA COQUlLLETT. BY F. M. WEBSTER, M.S. SEP (I 1969 UBPfJ~y ERRATA AND ADDENDA. Page 35, line 15, for 1854- read 1855. Page 55, line 16, for Horticultural read State Agricultural. Page 60, in second table, Illinois, for 240 read 241. Page 65, first line above foot-note, for ventricosa read ligamentina. Page 72, line 9, for imhecilis read imbecillis. Page 79, line 19, for asperimus read asperrimtts. Page 80, above Quadrula rubiginosa insert Section Fusconaia Simpson. Page 76. The record of Calkins for Margaritana margaritifera is without doubt erroneous and should be eliminated. This species is not found in Illinois. Page 95. Pomatiopsis sheldonii Pilsbry should read Amnicola sheldonii and should be transferred to the genus Amnicola on page 93. Page 100. Physa gyrina oleacea Tryon is the immature stage of Physa gyrina. Page 103. Lymncsa tazewelliana is a synonym of Lymncea parva. Page 105. Lymncea palustris michiganensis is the immature form of Lymncca rcflcxa. Page 106. Lymncza reflexa ioivensis and Lymncea reflexa crystalensis are synonyms of Lymncea reflexa. Page 112, line 6 from bottom, for goitldi read gouldii. Page 114, line 5 from bottom, for jnxtigcns read juxtidens. Page 115, line 21, for Witter read Walker; line 23, Polygyra sayii Binney should be changed to Polygyra sayana Pilsbry. Page 116, line 1. Polygyra exolcta Binney (1885) should be changed to Polygyra zaleta Binney (1837). Page 117, line 11 from bottom, for Icai read leaii; line 3 from bottom, Poly- gyra monodon fraterna is a good species and should read Polygyra fraterna. Page 119, foot-note. A specimen of alliarins in the collection of Mr. Aldrich, received from Calkins, proves to be draparnaldi. Page 121, line 3 from bottom, for Champaign read Piatt. Page 122, line 12 from bottom, for Pyramidula siriatella Anthony read Pyra- midiila cronkkitci anthonyi Pilsbry; line 4, for Held read Hald. Page 123, for Helicodiscus lineatus Say read Hclicodiscus parallcliis Say. Page 162, line 7, for glandulosa read linearis. Page 171, line 17, for riparia read vulpina. Page 176, line 8 from bottom, for canadense read majiis. Page 180, line 9, for virginica read virginiana. Page 221, line 6 from bottom, for rectangiiliis read rcctangttlaris. Page 226, line 3, for fasciatus read fasciata. Page 239, line 11, strike out Lake Co. entry. Page 246, lines 6 and 7, and page 248, lines 1, 14, 20, and 23, for CEnothera read Onagra. Page 248, line 4, for Candida Horn substitute n. sp. Pac^e 249, line 8 from bottom, for Olethreutes dimidiana Sodoff? read Olethreutes separatana Kearfott, and strike out parenthetical matter. Page 251, line 7, for grossa read thoracica; line 21, for words preceding H. 6, read Asilus rufipennis Hine; line 18 from bottom, for words preceding H. 2, substi- tute Asilus cacopilogus Hine. Page 253, line 8, for Linn, read Emory. Page 257, line 15, for pennsylvanicus DeG. read auricomus Rob. Page 261, Note 6. Melanoplus macneilli is very probably M. ftuviatilis Brun. Page 262, Note 9. Dr. Bergroth writes that Nabis elongatus is preoccupied. The original is elogantus in the check list. Comparison with long-winged vicarius is desirable before re-naming it. Page 309, in table, for 59 read 57, and for 743 read 741. Page 310, in table, for JS* read 57. Page 314, line 5, for 1587 read 481; line 16, after stubble insert meadows; line 17, after pastures strike out and meadows, and after 1600 strike out each. Page 315, last line, for 553 read 481. Page 362, line 7 from bottom, for longa read parvilamellata. Page 373. As a second entry in synonymy insert as follows: 1854. Nothrus bistriatus, Nicolet, Acariens des Environs de Paris, p. 397, PI. VII., Fig. 7. Page 376, line 13 from bottom, for Oribata read Oribates. Page 378, line 1, for XXV. read XXXV. Page 384, after line 5 insert as follows: N. bipilis Hermann. Mem. Apt., p. 95. In moss. Areola and Parker, 111. Page 384, line 5 from bottom, for pyrostigma read pyrostigmata. Page 386, after line 11 from bottom insert as follows: H. bistriata Nicolet. Acariens des Environs de Paris, p. 397, PL VII., Fig. 7. Under logs and in moss, Urbana and Areola, 111. Page 388, line 12, for sphcerulum read sphcsrida. Article I. — Studies of the Life History, Habits, and Taxo- nomic BeJettions of a New Species of OI)erea (Oherea ulrnicola Chittenden). By F. M. Webster. The species of this genus of Ceramhycidm are not easy to define, on account of their variability in color, and they have for this reason been the subject of repeated and radical revision by entomologists. In 1878, Dr. G. H. Horn, in his revision of the genus* restricted the number of species to eleven, while Mr. Chas. W. Leng, eighteen years later, reduced this number to five. In this latter revision Oheyea tripiindata Swederus v^^as divided in- to two groups, or forms as they are there called, the bi)nacN/ata form and the tripunctata form, the species itself being thus burdened with no less than eleven synonyms. Even this ar- rangement is unsatisfactory, and considerable evidence has ac- cumulated tendingto show that we may have species the adults of which are difficult to separate, whose larvae are restricted to very different food plants. Thus Otjerea hinuiculata has hitherto been reared exclusively from plants belonging to the genus liahns, while 0. tripunctata breeds in a variety of food plants other than RuJ)i(s, and including the elm. It is therefore inter- esting to find another apparently valid species which seems re- stricted to the elm, although 0. tripunctata, as at present under- stood, breeds on the same tree with the one under consideration. One of its close allies, Oherea texana, is a southern form, while 0. uJmicola has thus far been found only in a single city of about 20,000 inhabitants in central Illinois. Even there it does not infest the elms of the entire city, but has confined it- self to a certain section, within which it is so excessively abun- dant that the females are compelled to deposit their eggs in the same twigs again and again, notwithstanding the fact that only *Trans.Am. Ent. Soc, Vol. VII., pp. 45-48. \Loc.cit., Vol. XXIII., pp. 153-157. a single larva can survive in each twig. This congestion in num- bers and restricted distribution would commonly be taken to in- dicate a spirit of mutual toleration bordering on gregariousness. In this case, however, if adults of both sexes are confined at all closely together they will, regardless of sex, fall upon each oth- er, amputating antennse and legs with a savagery like that of the most bloodthirsty quadruped, and this vicious disposition is, in fact, one of the greatest obstacles to the close study of these insects in confinement. These studies are based very largely on the acute and un- tiring observations of Mr. E. S. G. Titus, formerly Assistant to the State Entomologist of Illinois and now an assistant in the Division of Entomology of the United States Department of Ag- riculture. The species was from the first regarded by him as probably new, and later, in connection with my own studies of insects infesting shade and ornamental trees, specimens were submitted to Dr. L. 0. Howard for identification, which revealed the fact that it was not represented in the collections of the Department of Agriculture, or in those of the United States National Museum. As Mr. F. H. Chittenden, of the Division of Entomology of the Department of Agriculture, had already col- lected considerable material for a study of the genus Oherea, he was invited to describe the species, and his description of the adult follows, together with a table prepared by him showing the relations of the species in the genus. DESCRIPTION OF THE SPECIES. The Adult. "While studying reared material of the genus Oherea, and referring to published accounts of the species, it was observed that in many references to economic literature the raspberry cane-borer was called Oherea tripuncfata Fabr. as well as 0. tri- punctata Swed. It has been conceded by Horn and others that the former name is synonymous with 0. himaculata Oliv., which, the writer is convinced, is quite distinct from 0. trijmnctafa of Swederus. We have recently had considerable correspondence with Prof. F. M. Webster, who has also reared these two species, as well as a third, and as his views correspond with the writer's, a table has been drawn up, after careful comparison of nearly a hundred examples of the first two species discussed and a lesser number of the third. "As a preliminary, it should be stated that the writer fully concurs in the views expressed by Dr. Horn* when he stated that the table furnished at that time, 1878, although founded on color characters, attained 'the object in view as nearly as can be done' ; also that the species were so variable, even with the sup- pression which he had made, 'as almost to resist generalization'. "The first two forms considered can readily be distinguished by color characters alone, examination of all available ma- terial showing these colors of sufficient constancy to leave no doubt as to the specific identity of a single specimen. More- over, the three species are physiologically distinct, being con- stant within certain limits as regarding habits, 0. hlmaeulata having thus far been reared only from canes of raspberry and blackberry [Buhus), 0. tripunctata from various deciduous trees, including dogwood {Cornus) and witch-hazel, while the third species is known only as inhabiting the elm {Ulmus). The three species now under discussion may be separated by the aid of the following table: A. Ventral surface (including legs and antennae) except thorax, black; abdomen somewhat coarsely and very sparsely punctate, with rather long, black or dark brown pubescence. Elytra with black pubescence, disc with prominent caringe, and deeply and closely punctate. Head somewhat strongly and densely punc- tate, with moderately black, brown, or dark yel- low pubescence bimaculata Oliv. AA. Ventral surface (including legs) largely yellow; ab- domen with punctuation feeble, obsolete, or wanting on some segments; pubescence short and pale. *Loc. cit. 4 Elytra with cinereous or griseous pubescence; disc more flattened, with less prominent carinse, less strongly punctate. Head less strongly and more sparsely punc- tate, more strongly pubescent with gray or yellow, a. Form slender, antennge long; head, an- tennae, and elytra mostly black, with cine- reous pubescence; elytra moderately, fine- ly, and sparsely punctate uhiueola Chittn., n. sp. aa. Form more robust, antennae shorter, black, or partly yellow; head with yellow or griseous pubescence; elytra largely yellow, more strongly and densely punctate, with very pale yellowish or griseous pubescence. tripunctata Swed. '^Oberea ulmicola Chittenden, n. sp. (PI. I., Fig. 1.) "Form slender. Head, antennse, and elytra black, with gray pubescence, becoming long and dense on the head, nearly obscuring the punctures, and darker plumbeous-gray on the thorax. Antennae slender, long, five-sixths of the length of the entire insect. Head somewhat feebly and sparsely punctate, with strongly defined median line, especially in the posterior portion. Thorax yellow, callosities black, occasionally with a smaller black antescutellar spot on each side; just above the leg there is usually another variable black spot, either smaller or much larger than the others. Elytra with basal portion on each side of and including the scutellum, yellow, occasionally with a longitudinal yellow streak on each elytron, extending from the base nearly to the apex, which is emarginate and sub-bidentate; the surface comparatively sparsely and feebly punctate. Epipleuree yellow. Ventral surface usually yellow, but occasionally with a portion of the thorax and of the second and third abdominal segments and less frequently the first and last segment, black. Punctuation very shallow, nearly obsolete on abdominal segments. Proximal portion of legs yellow, distal portion black. The sexual and other characters as far as observed differ but slightly from those of tripunctata and hiniaculuta. Length, 9-13 mm.; width, 1.2-2.0 mm. Average length, 12 mm. ; width, 1.9 mm. The small specimens are obviously stunted. "Habitat, Decatur, Illinois, where it breeds in twigs of the American elm, JJlnuis americana. Described from many speci- mens reared by Mr. E. S. G. Titus and collected by himself and Mr. Webster. "Type, No. 6981, U. S. National Museum. Kindly presented by Dr. S. A. Forbes, Director of the Illinois State Laboratory of Natural History. "This species has a somewhat strong resemblance, in dark individuals, to 0. biinaculata, while the pale forms approach 0. tripunctata. In reality it is nearer 0. texana in appearance, but has longer antennas than any of these. 0. texana is quite distinct in having the paler parts, thorax, and ventral surface red, epi- pleurae black, proximal portion of the legs reddish, head less hairy, and abdomen comparatively strongly punctate." At present it does not appear possible to separate the early stages of this group of species. While there are obscure dif- ferences, there do not appear to be the necessary positive ones. The Egg. (PI. L, Fig. 2.) Length, 3 mm. ; width, 0.6 mm. ; slightly reniform, of a creamy white color, without perceivable reticulations. The Larva. (PI. L, Fig. 3.) Length, 14 mm. Head much smaller than thoracic seg- ments, body decreasing in width posteriorly with moderate uni- formity to the eighth segment, which is considerably smaller, the anal still more reduced; body light straw-color, the two posteri- or segments lighter; head anteriorly dark brown, posteriorly the color of the body, mandibles darker than anterior portion of head. Cervical shield brownish yellow, anterior surface smooth polished, terminating posteriorly in a slightly raised, transverse ridge. The apical declivity is shagreened, more finely posteri- orly and centrally; narrow median dorsal area whiter; lateral oblique, sinuate grooves darker. In front of the shagreened area are a few short erect hairs, with larger ones placed laterally on this segment. On the next segment there are but two lateral hairs on each side, and none on other segments until the eleventh, which has a single stout bristle on each side considerably above the margin, and a transverse row of hairs along the posterior margin. The anal segment has a considerable number of long curved hairs along the lateral and posterior areas. The lateral margins of each of the abdominal segments, just below the spiracles, have an inflated appearance, and segments three to ten inclusive are strongly sculptured, especially on the dorsal surface, by transverse, tubercular, flattened ridges which are minutely shagreened. The sculpture of these is clearly shown in Fig. 3, PI. I. The lateral inflations, with deep intervening constrictions, give the larva when extended a somewhat monil- iform aspect. The Pupa. (PI. I., Fig. 4.) Length, 13 mm.; color uniformly light yellow; head with nearly triangular impressed area between the bases of the an- tennae, on each side of which are a pair of closely set hairs. There are two clusters of minute spinules on the clypeus. The antennae, being abruptly bent downward, give the head a de- cidedly square appearance. They extend backward to just be- yond the middle femora, where they turn forward along and out- side of the anterior and middle legs, the posterior pair of legs being folded under the wings. There is a minute, robust, hooked spine on the marginal ridge of each of the abdominal segments except the terminal, the hooks being reversed; there is also on each of these segments a transverse dorsal elevation armed with irregularly placed, minute, stout spines. The terminal s gment is provided with a number of long hairs. LIFE HISTORY. There is a single annual generation, the larvae hibernating in the twigs and finishing their development in the spring, the larval period being nearly eleven months. Pupation takes place within the twigs during late April and early May, the pupal period occupying from 22 to 29 days. The eggs are de- posited, in the vicinity of lat. 40°, in Illinois, from about May 20 to June 15. The egg period is from 5 to 7 days. METHOD OF OVIPOSITION. As observed by Mr. Titus, the female first girdles the ten- der growing twig by cutting, with her jaws, a deep groove en- tirely around it. The twig is then easily detached, and falls to the ground with the first light breeze that occurs. Retreating about an inch along the remaining portion of the twig, the beetle cuts a short longitudinal slit in and through the bark but not entering the wood, and at the lower end of this she cuts a shorter transverse gash, also extending only through the bark. She now pushes the tip of her abdomen under the bark at the angle formed by the two gashes she has made, usually to the right of the longitudinal slit but sometimes to the left, and places her egg snugly under the young tender bark, some- times nearly a fourth of the way around the twig, where it can be easily detected by the slight elevation thus caused. Having placed her egg, she now retreats still further toward the base of the twig, usually about an inch, and here girdles it a second time, but cutting only to the wood, thus crippling the twig without killing it. If the same female deposits more than one egg in the same twig, she does it at different times, the evident intention being to place them singly, one in each tw^ig, and as shown in Plate I., Fig. 2. HABITS OF THE LARVA. The young larva, on first hatching from the egg, begins to feed even before it has entirely emerged, gnawing a minute channel toward the base of the twig and under the bark long enough to enable it wholly to withdraw the body from the egg- shell. It then seems to back up into the abandoned shell and cuts a minute circular hole in the bark directly in line with the channel. Up to this time all of the castings have been pushed back into the egg-shell, but now they are pushed out through the circular hole thus made. Working now down the center of the twig and continually enlarging its burrow, the larva pro- vides at intervals similar but larger vents in the walls for the same purpose. In this species these holes for the disposal of excreta and waste material do not appear to be as frequently cut as in the case of allied species, the distance from one to an- other ranging in our specimens from a little over an inch to more than two inches. Several years ago, while studying similar habits of what I then supposed to be Oberea bimaculata, but now know to have been 0. tripuudata, I observed these holes to occur frequently not more than an inch apart, and the excreta were pushed through and fell down in more or less continuous sections. In two cases the masses of excreta thus disposed of by a larva of that species nearly full grown and about an inch in length during the twenty- four hours, were kept and carefully measured. Their length amounted to the astounding total of twenty-four and three eighths inches, showing that each hour of the day and night the larva had voided a stool greater than its own length,—a fact which gives some idea of the enormous amount of food eaten within that time.* As the larva increases in size it frequently reverses its posi- tion in its burrow, and moves up and down at will. These journeys are easily accomplished by the simple contraction and expansion of the segments of its body aided by the shagreened areas on the dorsal surface. Just prior to pupation, the larva gnaws out a cavity in the wall of its burrow similar to that constructed for the disposal of the excreta, except that it does not penetrate the outer bark. An avenue of escape is thus pro- vided for the adult beetle without exposing the pupa. Pupation occurs within the burrow, and only a few minutes are required for the escape of the beetle from the pupal envelope. Secure as they may appear to be in their channels, the larvae are not without their troubles, for not only the main *Journ. N. Y. Ent. Soc, Vol. V., pp. 202-203, ^^- X., Fig. i and 2. 9 twig is inhabited but the laterals as well, and there may thus be several larvae, each in its individual twig, pushing down- ward to the base, in which but one of them can survive. The one that is foremost in this blind race, as it passes below its fellows cuts off their food supply and leaves them to perish in their homes. In some instances larvae have been observed to pass the whole length of water-shoots and for a short distance into the wood of the tree itself. The effect on the trees is to destroy the growth of shoots put forth prior to the middle of June. This injury, continued year after year, results in bunches of dead stubs, a clump of which is shown in the colored plate (11.), drawn from a speci- men cut by me from a tree in one of the parks in Decatur. The short blackened stub to the right shows the work of the larvae two years ago; the longer one to the right of it, with the two blackened laterals, shows the work last year; while the green and brown shoots show the effect on the twigs the pres- ent season. The single small twig at the extreme right, which sprang out from the base of a larger one already affected, was the only one of the cluster that had escaped destruction, it having been put forth after the beetles had disappeared. By another year this whole group of twigs would have become hollow blackened stubs. Fresh growths being attacked and destroyed in the same manner, the cluster of dead stubs is in- creased year after year. In such a case as that of the unin- jured twig at the extreme right in the colored plate, the larva would continue its work another spring and, passing below the juncture, finish the destruction of the groap. HABITS OF THE ADULT INSECT. Two very striking peculiarities were observed by both Mr. Titus and myself. In the twenty-five years that I have been studying the habits of insects, I do not recall an instance of such seemingly utter disregard for the perpetuation of the species as is exhibited by these beetles. The vicious assaults which they make on each other, regardless of sex, are paralleled only among the Mantkhe and some species of spiders. While I 10 did not notice any conflicts in the open, we both experienced the utmost difficulty in keeping the adults in sufficiently close quarters to enable us to study their actions. If a male and female were confined at all closely, they would instantly attack each other with such ferocity that within a few moments they would be rolling helplessly about among fragments of legs and antennae, only the basal portions of these remaining attached to their bodies. It was found wholly impossible to transport living individuals without giving them ample quarters, and I was finally forced to give each a box or vial to itself. The other peculiarity referred to is alack or insufficiency of the dispersal instinct when the beetles become excessively abundant in a locality. Though no trace of them was found in some parts of the city of Decatur, in other parts they were so abundant that the young growth of the elm did not afford them sufficient material in which to mature more than a small percentage of their larvae, only one of which can develop in a single twig, but instead of hunting for other trees where suit- able conditions existed, the females girdled the twigs and de- posited the egg where this had been done, not only once, but time and time again, before. I have found twigs in which there had been as many as eight separate ovipositions, with the usual number of girdlings in each case. The upper figure in the colored plate affords a very good illustration of a multiplicity of ovipositions, as also one of the twigs in the cluster below. We have here, consequently, what might almost be termed insect infanticide on a stupen- dous scale. But the full extent of this wholesale murder does not appear in the illustrations. In all examinations of the am- putated portions of the twigs made by Mr. Titus, he found none which contained eggs or larvae, and this was true of my own ob- servations, made during the early part of the egg-laying season. Late in May, however, I began to find sections of amputated twigs on the ground underneath the trees, which showed plainly that this amputation was not the result of a first visit of a female intent on oviposition. Ordinarily, the tip of the twig is severed far 11 enough back to include from two to four or five leaves, and this amputated portion is free from egg or larva. But I now began to find, scattered under the infested trees, pieces of twigs which had been cut off at both ends, and those freshly dropped con- tained in most cases either an egg or a newly hatched larva, while in the older, withered ones there was more often a very young larva, dead. As the season of oviposition advanced, these secondary amputations, repeated perhaps five or six times on the same twig, became more numerous, and an examination of the trees disclosed the fact that nearly every twig contained at least one egg or larva, and that some of them contained several. For those females that had yet to oviposit, there were no twigs not preoccupied, and fully five percent, of the amputated pieces on the ground contained a larva or an egg. It became clear that the mortality resulting from this repeated oviposition and am- putation was greater than that from all other causes combined. The beetles appear to feed but little, and then only on the leaf veins, as shown in Fig. 5, Plate I., and at the extreme right of the colored plate. Neither Mr. Titus nor myself found them feeding on any other part of the leaf, or any indication of their having done so, even when confined in breeding-cages. FOOD PLANTS. It would seem from the information thus far obtained, that this species confines itself strictly to the American elm. While the beetles will, if confined on other plants exclusively, feed sparingly on the leaves, they will not oviposit in the twigs, but if removed and placed on elm, they will proceed to deposit their eggs. Adults of both sexes confined on raspberry May 20, were all dead by May 29, having in the mean time shown no inclina- tion whatever to oviposit, though the sexes were observed in the act of pairing. The same was true of those confined on Cornus; but when removed, these females oviposited in elm. These state- ments are taken from Mr. Titus's notes, and my own experi- ments simply duplicated these results. Though I found Oberea larvae in other kinds of trees in the parks at Decatur, I am con- fident that these belonged to another species, probably Oberea 12 tripunctata,whichwsiS 3Aso reared from elm-trees infested hj ul- micola. No experiments were tried with other species of elm. NATURAL ENEMIES. As may be seen from the foregoing, this species is its own greatest enemy. No egg parasites have been found, though such may confidently be looked for in the future. That the eggs are to some extent destroyed by birds, appears probable, though none were observed in the act. Nuthatches were pres- ent in the trees, both in those infested and in those free from the pest, and the frequent occurrence of twigs with the bark pushed upward and outward at the point where the egg is usually placed, as is shown in Plate XL, upper figure, suggests clearly that some feathered enemy had pushed its beak beneath. As this lifting of the bark was noticed only on the side of the longitudinal slit where the egg is usually placed, it is fair to presume that either the egg or young larva had been removed. GENERAL EFFECT ON ELM-TREES. The production of bunches of short twigs which are annu- ally killed and replaced by others, these suffering in turn in the same manner, has been already described, and the inevitable effect on the general appearance of the trees will be clear to any one at all familiar with the growth of young elms. They gradually assume a scraggy, stunted, and misshapen appear- ance, with the foliage inclined to grow in tufts about the larger limbs, the latter throwing up an unusually large number of wa- ter-shoots, which, being killed down each year, add to the un- sightly appearance of the tree. The limbs may increase in size but not in length, as each year's growth is killed back the same year. Sometimes the larvae working in spring pass be- yond into lateral twigs which had escaped attack and cause their death. I have found lateral twigs and fresh growths withering and dying from this cause as late as the latter part of May. Larger trees do not show the injury as much as smaller ones, but even the former will lack the broad, wide-spreading growth so much admired in the elm. Not all trees standing in 13 close proximity are affected alike. Some will be girdled com- paratively little, while others, perhaps but a few rods away, will suffer a most serious pruning. It would seem as though the beetles were disinclined to forsake the trees from which they had themselves emerged,—a supposition strongly sup- ported by their extremely local distribution. DISCOVERY OF THE SPECIES. The attention of the custodian of the Decatur city park was first attracted to the insect by the enormous dropping of the leaves during late May and June, this increasing the labor re- quired to keep the grounds in proper condition. The facts were first reported totheState Entomologistin October, 1901, atwhich time it was said that the injury had been noticed forsome two or three years preceding, becoming more serious each year. The tips of the twigs, with from three to six leaves attached, appeared to have been cut squarely off in a way to suggest the work of an insect, but of the author of the injury itself nothing had then been learned. May 23, 1902, Mr. Titus was sent to Decatur by Professor Forbes to learn the cause of the injury, and it was during this visit that he first secured material for his studies of the habits and life history of the species. This was supplemented by further accessions from the trees during the remainder of the season, and by carrying the females with him, in his travels about the state, Mr. Titus was enabled to secure the facts here given relative to oviposition and to the actions of the very young larva. Other data were obtained by carrying the insect through the year in the insectary. The writer took up the investigation in the spring of 1903, and was able to add somewhat to the re- sults of the careful work of Mr. Titus, as well as to clear up some points on which the latter had not been able to secure conclu- sive evidence. 14 EXPLANATION OF PLATES. Plate I. The Elm Twig-girdler, Oberea ttlmicola Chittenden: a, adult beetle; b, egg, enlarged and in position under bark of twig: c, larva, d, pupa, e, showing leaf-veins eaten out by beetle in feeding. Plate II. Elm Twig-girdler, Oberea ulmicola Chittenden; a, illustrating girdling of twigs by adult and the general effect on the young twigs, the original having been cut from an elm-tree in a city park in Decatur, 111.; adult shown engaged in feeding on leaf at right; b, a much girdled twig illustrating the effect of birds in search- ing for eggs or young larvae. Injuries caused by Elm Twig-girdler ( Oberea ulmicola Chittenden).