as the first week in July, and these late galls, as well as the insects within them, are generally more yellowish than those found earlier in the year; but a careful study of the structure of the inmates shows them to be identical with those found in the earlier galls, and these late galls are, from present knowledge, to be attributed to the work of late hatching and late developing stem-mothers rather than to the work of the third generation. I am inclined to think that this third generation will be found to have a different habit, possibly feeding upon some other part of the tree, without forming galls, and producing in time the true sexual individuals, something as in the case of the seventh generation of S. americana. At all events, the true female (Fig. 2, b), with the solitary egg, is to be found about the trunk of the tree, as already described. DESCRIPTIVE. COLOPHA ULMICOLA. Byrsocrypta ulmicola, Fitch, 4th N. Y. Rep. 1858, p. 63 (§ 347).—Thelaxes ulmicola, Walsh, Impregnated or winter egg (Fig. 2, b).—Length 0.38mm, perfectly ovoid, shining olivaceous, inclining to brown, with no particular sculpture. First generation, or stem-mother.-0.4mm long when hatched. Antennæ 4-jointed, joints subequal in length and thickness, but with the bases of hairs rather strong. Promuscis very short, reaching only to middle coxæ or a little beyond. Upper tarsal hairs globate at tip and as long as tarsus. Smooth, dark olive-brown in color with black members. After first molt, the beak is still relatively shorter, as also the tarsal hairs; the color is paler, but the members are still black. She measures 1mm in length when beginning to bear, and the third joint of antennæ is then somewhat clavate (Fig. 2, g), and as long as joints 1 and 2 together; the 4th narrower, as long as 3d, and rather truncate at tip, with two rather conspicuous piliferous prominences. Color translucent yellowishgreen, often inclining to purple. Second generation.-0.4mm long when born (Fig. 2, c); nearly five times as long as wide; the antennæ (Fig. 2, h) short and 5-jointed, the joints subequal in length, the 3d shortest and narrowest, the 5th swollen and sub-fusiform, with rather strong bulbs at the base of the hairs. Promuscis reaching to hind coxa. Distinct globate tips to the four tarsal hairs. Color pale olive-green, with black members and a dusky stripe on the notum. Pupa (Fig. 2, d) with antennæ smooth, 6-jointed, joints subequal in thickness, joint 4 only as long as 2; 5 and 6 each twice as long; 3 four times as long. Color dingy orange, with a paler band around the thorax, embracing the wing-pads, and reminding one, on this account, of the pupa of Phylloxera. Winged female (Fig. 2, e) : Average expanse 3.7mm; the form of body more as in Phylloxera, the abdomen tapering and narrower than the thorax, bearing from ten to twenty pseudova. Blackish, with an olive-green tint, the abdomen and under surface yellowishgreen in the fresher individuals. Antennæ (Fig. 2, f) reaching only to insertion of front wings, 6-jointed; joints 4, 5, and 6 subequal, and together equal to 3 in length. [Three specimens examined have joints 4 and 5 very imperfectly separated, causing the antennæ to appear as 5-jointed.] Wings as described by Walsh, the stigma being well rounded and pale. [In three specimens examined, the third discoidal of the front wing is simple and precisely as in Pemphigus; in one specimen, the first discoidal is wanting on both front wings, and in another the fork of third discoidal is wanting on the left one.] Basal joint of tarsus rather short; tarsal claws only moderately strong. Third generation.-The young from the winged female, after being freed from the pellicle in which they were born, have stout five-jointed antennæ, the joints subequal; stout but short promuscis reaching to hind coxæ; rather large compound eyes. Proportions and shape of young Phylloxera. True female: Legs short and the basal joint of tarsus rudimentary; antennæ short, four-jointed, smooth, joints subequal, the third somewhat longest. Mouth rudimentary. Described from skins surrounding impregnated egg. Males unknown. PEMPHIGUS POPULI-MONILIS, n. sp. [Gall (populi-monilis) on the Narrow-leaved Cottonwood (Populus balsamifera). A series of more or less confluent moniliform swellings (Fig. 3, g) on the upper side of the leaf, each containing a single female, destined to become winged, when it escapes from beneath, the winged insect occupying the entire cavity of the gall.] BIOLOGICAL. A very interesting gall, which may be called the Bead-like Cottonwood Gall, occurs on the Narrow-leaved Cottonwood (Populus balsamifera, L., var. angustifolia, Torrey), during the summer, in Colorado, and probably wherever this narrow-leaved variety grows. Though I have often found the tree in question so covered with these galls, especially at Greeley, that not a leaf was exempt, yet Populus monilifera, even when growing along the bank of the same irrigating ditch and mingling its branches with angustifolia, would be entirely free from them. The galls when not very numerous appear most commonly on the terminal leaves of a twig. They form a confluent series of pale yellow ovoid swellings, each side of the midrib (Fig. 3, g) recalling, in the distance, a lot of unripe cherries, or, again, the galls produced on a true willow by the Sawfly larva-Nematus salicis-pomum, Walsh. There will sometimes be three rows of these swellings, and they are not infrequently tinted with red. There are, however, more often but two rows, occupying nearly the whole space each side of the midrib. The galls are formed by the folding-under of the sides of the leaf and the bulging of the same around the insect, which is always found solitary. The newly hatched louse is found in the younger galls, and on the same branch, according to the age of the swelling, the insect occurs in all stages of growth, the full-fledged female, with her wings folded flat, filling nearly the whole cavity. After leaving the gall, her wings are carried in the normal tectiform manner, and, when rendered transparent by liquid, her abdomen is seen to be swollen with fifty or more egg-like bodies, the dark eyes of which show conspicuously. These bodies are the pseudova, and the female commences at once to deposit them upon issuing from her dwelling. The young, which free themselves in the course of a few minutes from the confining pellicle, are of a pale yellowish-green, with black eyes. In structure, these young differ only from the preceding generation, at a similar age, by the somewhat narrowed body and by the promuscis reaching beyond the anus. Just where these young are deposited by the winged mother, I have not had opportunity to ascertain. They probably found new galls, the process continuing until the late summer or autumn generation of winged females give birth to the sexual individuals, and these consign to the permanent parts of the plant the winter egg. The probability is, also, that the stem-mother that hatches in the spring has a different habit, producing not improbably a quite different gall. DESCRIPTIVE. PEMPHIGUS POPULI-MONILIS, n. sp.-Winged female (Fig. 3, a): Average expanse 6.5mm. Black, the abdomen a little lighter, especially at the tip. Finely powdered with white; broad across the shoulders, the scutellar lobes of the mesonotum being rather more flattened than the præscutum; the head rather small and narrow. Antennæ (Fig. 3, b) and legs rather short, the former reaching only to base of front wings; 6-jointed; joints 1, 2, 4, and 5 subequal in length; 3 twice as long; 6 not quite as long as 3. Joints 1 and 2 very stout; 3, 4, and 5 somewhat clavate; nearly smooth above, but with about twelve deep constrictions beneath. Legs normal, with basal joint of tarsus (Fig. 3, ƒ) tolerably well separated, and unguis stout. Wings subhyaline; front wings with stigma strongly angulate, dusky, the lower portion almost black. Veins dusky, the costal and subcostal stout and darkest. Stigmal vein undulate, starting from a little beyond the middle of stigma. First and second discoidals almost connected at base [in three specimens entirely so], and the distance between them at tips about one-third greater than between 2d and 3d discoidals, and that between these two subequal with that between the last mentioned and stigmal; the 3d discoidal obsolete toward base. Fold of hind border but moderately thick. Hind wings ample, the hook-angle but moderate, the subcostal slightly undulate and considerably elbowed at basal third, whence spring the discoidals, the first bending slightly toward posterior margin, the second toward costal margin, the spaces between the tips of the costal and the discoidals subequal, and together rather more than half of posterior border. [An examination of fourteen specimens only showed one with the third discoidal forked on both wings, and another with the same vein forked on the left wing, and the second discoidal also forked near tip.] When newly hatched, or in the first age, the basal joint of tarsus is scarcely perceptible, and the tarsal hairs are simple; the antennæ (Fig. 3, c) are 4-jointed, the basal joint half as long as the 2d; 3d and 4th somewhat longer and subequal; the 4th suddenly narrowed at tip; the pronuscis reaches beyond hind coxæ. After first molt, the antennæ (Fig. 3, d) are 5-jointed, the 4th very short and almost globular: the promuscis now reaches to the middle coxa only. In the pupa state, the antennæ are 6-jointed. Young from winged female similar to the same stage of its parent, except in the promuscis reaching beyond anus (Fig. 3, e). Length 0.15mm. Throughout Central Colorado, July (Riley); Southern Kansas (Monell). HORMAPHIS SPINOSUS (Shimer). [Gall (hamamelidis-spinosa) on stem of Hamamelis virginica in autumn, being a deformation of the fruit-bud.] Another gall (Fig. 4, a) I have found in autumn on the stems of the Witch-hazel. It is made by a new species of flocculent plant-louse, congeneric with one that is known to make conical galls on the leaves of the same plant. The gall is a deformation of the flower-bud, the puncture of the architect causing premature development, by which the calyx, bractlets, and petals are all changed into elongate bracts, more or less pointed terminally, and more or less completely soldered together at bases, so as to form a thin wall. In August, the gall is green and crowded inside with lice in all stages of growth, from the newly-born to the pupa and winged female, intermixed with flocculent matter and watery globules, the insects themselves being rather evenly covered with a fine white powder. Later in the season, the tips of the bracts become blunter, and the gall becomes browner, and recalls externally the fruitpod which would have developed the ensuing year. It is now perforated at some point, generally near either the top or base, and through the aperture the insects have either made their exit or may be noticed doing so. The young from the winged female are quite characteristic, being strongly granulated, and, as they were found as late as the end of October, they probably hibernate on the permanent parts of the tree. The sexed individuals and the stem-mother are yet unknown. The species was first described in 1867 by Dr. H. Shimer of Mt. Carroll, Ill., who erected a new genus for it and another well-known species on the same plant, not aware that the genus had been previously characterized by Baron Osten Sacken, in 1861. HORMAPHIS SPINOSUS. Hamamelistes spinosus, Shimer, Trans. Am. Ent. Soc. i, p. 284, 1867. Winged female (Fig.4, b): Expanse 5mm. Color dark brown, uniformly pulverulent, the abdomen slightly paler and filled with egg-like bodies. Head with a frontal tubercle, and with the promuscis not reaching to beyond front coxæ. Antennæ (Fig. 4, d) reaching to base of front wing; 5-jointed, joints 1 and 2 bulbous and smooth, the others with about 50 close and regular and well-defined annulations; joint 3 six times as long as 1 and 2 together; joints 4 and 5 each half as long as 3, the terminal joint not being narrowed at tip. Thorax with the pronotum well defined, mesonotum having a thickened anterior border, with two small angles in front; the scutellar lobes and præscutum small. Tibia with a lobe each side at juncture with tarsus, the basal joint of tarsus not distinctly separated, and the tip furnished with two superior, knobbed hairs. Wings hyaline, the stigma and costal area fuliginous, the stigma pointed, but only slightly broadened; first discoidal almost transverse, second do. starting from it at upper third; cubital running straight toward base of first discoidal, but usually obsolete at basal half; terminal space between second discoidal and cubital wider than between it and the stigmal. Hind wings with the hooks strong, the costal vein straight, and a single discoidal, the first being obsolete. [Out of 20 specimens examined, I find the basal portion of the first discoidal of front wing connecting with the second at base, either on one wing (2 specimens) or on both wings (4 specimens), and in two cases this first discoidal is complete on one wing and incomplete on the other.] Larva quite broad and squarish anteriorly, with a frontal tubercle (Fig.4, h), and with the antennæ 4-jointed; promuscis reaching to hind coxa; color brown, with mesonotal lobes more yellowish. Transverse dorsal rows of four piliferous spots are faintly observable. Antennæ after first molt 5-jointed, and promuscis hardly reaching to middle coxæ. Pupa with similar antennæ and somewhat shorter promuscis. Young from winged female (Fig. 4, e): Resembling the larva of preceding generation, but distinguished by the absence of frontal tubercle, and by having the surface, except mesio-ventrally, evenly and conspicuously granulated. The terminal joint of antennæ also shows some constrictions (Fig. 4, g). PEMPHIGUS POPULI-TRANSVERSUS, n. sp. [Gall (populi-transversa, Fig. 5, a-b) formed upon the petiole near the base of the leaf of Populus monilifera and P. balsamifera. An elongate-oval swelling, causing the curving and broadening of the petiole, and opening on the opposite side by a transverse slit, with a whitish, slightly thickened, and elevated margin, recalling human lips. By the latter part of June, the stem-mother is surrounded with young of various sizes, all covered with the usual white secretion, and mixed with the liquid globules. Winged females produced in autumn, sometimes not until the leaves have fallen.] Winged female (Fig. 5, c): Expanse 7mm. Pruinescent, with the abdomen more yellowish, inclining to green. Antennæ (Fig. 5, d) reaching a little beyond the base of front wings; smooth; joints 3, 4, and 5 cylindrical, and of equal thickness; 3 as long as the other two together; 6 more slender at base, and with the apical unguis nearly as long as 3. Thorax with mesonotal swellings small. Terminal distance between 1st and 2d discoidal veins of front wings nearly equal to that between this last and the stigmal vein; discoidals almost connected; cubital obsolete at base; subcostal heavy; stigma scarcely wider than subcostal space, acuminate at tip, and with the vein starting a little in front of its middle. Hind wings with the discoidals connected at base, where the subcostal is slightly produced. Legs normal. Abdomen showing about 30 pseudova, and with 4 dorsal rows of faint piliferous dots. Pupa with joints 1, 2, 4, and 5 of antennæ subequal in length. The wingless forms are pale creamyyellow, with faintly dusky members. Missouri, Southern Texas, and Colorado (Riley). May possibly be popularia, Fitch, the description of which does not admit of identification. This gall occurs all over the West and Southwest, and while it normally occurs in the position and of the form described, it may occur on any part of the petiole, and the opening may be more or less oblique, or form a mere circular hole. Sometimes two and even three coalesce. The lip-like bulging is, however, constant. In the galls, after they had fallen to the ground, I have found in Southern Texas a number of large, yellow, apterous females of an undescribed Phylloxera, surrounded with their numerous eggs and with young of all sizes- -a fact that would be extremely confounding were Phylloxera and Pemphigus not so easily distinguished. PEMPHIGUS POPULI-RAMULORUM, n. sp. [Forming an irregular globular gall (populi-ramulorum), often somewhat flattened, on the twigs of Populus balsamifera in Colorado. The gall averages 15mm in diameter, and opens in a suture sometimes transverse, sometimes oblique, but more often longitudinal with the axis of the twig: exceptionally the opening is round and bulging. Green when fresh, it becomes gray and woody with age.] PEMPHIGUS POPULI-RAMULORUM.-Winged female: Alar expanse 6.8mm. Black and pruinescent, scarcely distinguishable from populi-transversus, except by the more annulate antennæ, the 4th, 5th, and 6th joints of which are much narrowed at base. The 6th joint (including subjoint) scarcely as long as 3d. The pupa is yellowish, with black eyes, and pulverulent. Colorado (Riley). Several of the species of Pemphigus forming galls upon Populus so closely resemble each other that they could not well be separated as species were it not for the differences in the galls they produce. Future careful investigation may show that the same species will produce different abnormities, and be slightly modified in appearance according as it affects different parts of the plant; but until we have such proof, the presumption is that the different galls are produced by distinct species, however similar the architects are in general appearance. PEMPHIGUS ACERIFOLII, n. sp. [Living in abundant and long cottony excretion, on the under side of the leaves of Acer dasycarpum, causing them to curl, and exuding an abundance of thick and very glutinous "honey-dew."] PEMPHIGUS ACERIFOLII, n. sp.-Winged female: Alar expanse 10mm. Head and thorax bluish-black. Abdomen black, covered with long cottony threads. Antennæ reaching the wing-insertions; annulations not conspicuous; joints 3, 4, 5, and 6 somewhat contracted at base and apex; apical unguis not perceptible; joints 5 and 6 |