Disholcaspis quercusmamma (agamic)

Rabdophaga salicisbrassicoides

Rabdophaga strobiloides

Rabdophaga salicisstrobiliscus

Rabdophaga salicisgnaphalioides

Rabdophaga salicisrhodoides

Rabdophaga saliciscoryloides

Rabdophaga saliciscornu

Rabdophaga rigidae

Rabdophaga salicistriticoides

Rabdophaga salicisnodulus

Rabdophaga salicisbatatus

Iteomyia salicisverruca

Eriophyes semen

Aculops aenigma

Amphibolips quercusjuglans (agamic)

It is a suggestive, and certainly not a merely fortuitous fact, that those Gall-flies which inhabit promiscuously several species of Oak, confine themselves to one or the other Section or Subgenus: eg Cynips q. globulus Fitch, occurs on Q. alba and Q. montana, and also, unless I have been deceived by the similarity of the gall, on Q. macrocarpa, all three of them belonging to the first section or subgenus.

Salicis brassicoides. n. sp. — On Salix longifolia [interior]. 

Monothalamous, sessile galls, expanding each 0.75 — 2.25 inch, and with the general outline of each spherical or oval, growing in a more or less close-set bunch of 1 — 11, like the sprouts of a cabbage-stump, on twigs which vary in diameter from .10 inch to .50 inch, sometimes from their tips but more generally from their sides, and often with several minute twigs growing from the midst of each bunch of galls, the largest galls generally on the largest twigs. The leaves composing each gall are all sessile, and are on the outside ovate lanceolate or lanceolate, and widely expanded and towards their tips recurved. Towards the tip of the gall they become smaller, slenderer, and gradually less expanded, and in the centre they are quite small, perfectly straight and linear-lanceolate, closely embracing the central cell containing the author of the gall. External leaves with the midrib, and generally some of the branching side-veins, pretty distinct. It is but very rarely that the leaves composing each gall show any traces of the peculiar, widely-removed serratures which characterize the leaves of the willow on which they occur, their edges being almost invariably perfectly entire. The color of the galls when recent, is the same as that of the recent leaves of the willow on which they grow, but at the fall of the leaf they become reddish brown, and after hanging on the twig more than one year, almost black. 

Described from 19 bunches of galls. Very common near Rock Island, Illinois. The eggs that originate these galls must be laid from the middle of April to the end of May, and by the middle of July the galls have attained their full size. When the twig on which they grow is at all small, it generally dies the next spring.

S. strobiloides O. S. 

On S. cordata [eriocephala?]. 

A monothalamous gall like a pine-cone, always on the tips of twigs when young, but often with small shoots of the same year's growth surrounding it, porrect, .50 — .90 inch in its transverse diameter, and in stunted galls where the gall-maker has perished even as small as .20 inch in diameter, generally when viewed laterally with an ovate outline and the tip more or less truncate, occasionally subspherical. The leaves com- posing it are all sessile, closely appressed and imbricate, and all those on the outside are covered with a short, dense, glaucous-white pubescence on their entire exterior surface, and occasionally in a less degree on their interior surface, and are reddish-brown inside when mature, those on the inside of the gall becoming gradually smooth and reddish-brown on their exterior basal portion, and finally throughout. Towards the base of the gall the leaves are orbicular, the basal ones smaller; the next leaves are obovate and with their tips in a semicircle, and as they approach the tip of the gall oblanceolate, and in the inside linear-lanceolate and gradually smaller, slenderer and straighter, till they finally embrace the central cell containing the author of the gall. External leaves, except towards the tip of the gall, with a number of branching veins springing from their base, the midrib scarcely distinct from them by its supe- rior size and throwing out similar branches, all of them obvious on the internal face of the leaf and obsolete on its external face. The tip of the twig from which the leaves spring, both in this and the 4 following species, is constructed as in C s. brassicoides. 

Described from 30 specimens. Very common and abundant in Rock Island County, Illinois, hundreds of them occurring on, a single bush. None of the leaves composing this gall are ever serrate, as in the willow on which it grows, but always entire. When young and immature, the galls are spherical and are enveloped in a dense mass of foliage, which gradually falls off towards the autumn, and by November the twigs on which they grow, if small, are already killed for an inch or two down- wards. Occasionally at the extreme tip of the gall the leaves open out a little, as in S. strobiliscus n. sp., but without projecting from the tip as in that species. Easily distinguished from that gall by the portion of each leaf which lies "to the weather," towards the base of the gall, not terminating in a rectangular point, but describing a circular arc. The leaves are also more densely pubescent, especially the portion that lies " to the weather." Appears early in the summer and is full-sized by the middle of July, at which time that which is reddish brown in the dry gall is greenish white. The pubescence on the leaves retains its glaucous-white color to the last, except where they are badly weather- beaten. On the same bush throughout the summer may be seen the old, dry, last year's galls, and the young growing galls of the current year. I have already referred to the Orchelimum eggs often found under the scales of this gall. In one gall examined this autumn I counted no fewer than 71 of these eggs. In September I detected a species of Xiphidium, which according to Mr. Uhler is undescribed, ovipositing in the pith at the tip of a broken stem of Goldenrod (Solidago). Probably Locusturiae Latr. (=Gryllidae Leach) do not so generally oviposit in the earth as authors have hitherto led us to believe. 

S. strobiliscus. n. sp. 

On S. rostrata [bebbiana], a high northern willow not found near Rock Island. I only know this species from a single dried and mature specimen received from Mr. Bebb. and gathered in Winnebago Co., on the extreme northern border of Illinois. It has a diameter of .70 inch and differs from S. strobiloides O. S. 1st. In the tips of all the leaves on the outside of the gall, and not merely those towards the tip of the gall, being angulated not rounded. 2nd. In their external surface not being so strongly pubescent, especially the portion lying "to the weather." 3rd. In the leaves at the tip being almost linear or parallel-sided instead of oblanceolate, and proportionally about 1/2 longer so as to project in a kind of beak from the tip of the gall. 4th. In the tip of the gall being more open than is usual in S. strobiloides. 5th. In the veins even on the inside of the leaves being subobsolete. The cocoon, as far as can be judged from what remains of it, was similar to that of S. strobiloides, but unfortunately it contained, not the larva or pupa of the Cecidomyia, but a parasitic Callimome, which infests several of these Gall-gnats, in the imago state. Hence, and from the fact of there being catkins in flower on the twig on which it grew, we may know that the specimen was about 10 or 11 months old when gathered. As usual in mature S. strobiloides, the twig on which it grew had been killed immediately below it for the space of h an inch or so. Since it might possibly have been the case that it was this species, and not my S. strobiloides, which was named strobiloides by Baron Osten Sacken, as he merely describes his gall as being "in the shape of the cone of a pine and an inch or more long," I communicated to him the distinctive characters between the two species, and he has been kind enough to inform me that my S. strobiloides is identical with his. The specimens which he originally used were obtained in Northern Illinois, and he tells me that he afterwards gathered a single one in Massachusetts, so that we know of this one gall, at all events, that has a wide geographical range. 

Larva, pupa and imago unknown.

S. gnaphalioides, n. sp.

On S. humilis.

A monothalamous, small, solitary, oval or sometimes subspherical gall, ,23 — .55 inch long and .14 — .60 inch in diameter, almost always growing at the tip of a twig and without any side-shoots around it, very rarely from the side of a twig from a small side- shoot no longer than itself, sometimes porrect but oftener with the last inch or so of the twig on which it grows curved downwards, or angularly bent down- wards, or coiled 2 or 3 times round like the tendril of a vine. The leaves composing it are imbricate, sometimes more or less loosely appressed, (when it resembles somewhat the little lemon-yellow garden-flowers known as "everlastings" or ''immortelles" or the indigenous Gnaphalium polycephalum,) but more usually opened out towards their tips, and always with their extreme tips more or less pinched together so as to form a kind of beak and frequently reflexed. These leaves are all entire, sessile, pale green in the summer and in the autumn of a pale reddish brown or pale yellowish brown color with fine, appressed, whitish pubescence on their external surface, and they have a few in- distinct longitudinal veins but no normal midrib and side veins as in S. rhodoides. At the base of the gall they are small and orbicular, then larger and orbicular, then oval, then towards the tip of the gall elongate-oval and elongate-obovate, the tip of the leaf in each case taper-pointed in an angle of about 80° so as to form the beak before spoken of. In the inside they become linear- lanceolate and envelop the central cell as in the preceding species. Described from 72 specimens. Attains its full size by the end of July, and is quite common near Rock Island. Illinois. In two or three cases where the potato-like gall S. batatas n. sp. grew at the tip of a twig, I have noticed the gall S gnaphalioides growing sessile from near the tip of the other gall, evidently from one of the buds included in it. In November I have observed that many of these galls have the larva picked out of them, evidently by birds, and in February full I of them are thus emptied, the leaves of the gall being pecked off on one side. This does not occur with the allied galls S. brassicoides, S. strobiloides, and S. rhodoides, probably because the larva is there concealed and protected by a much thicker wall of leaves; but I have repeatedly in the winter noticed the same thing of the large, spongy gall of the Dipterous Trypeta solidaginis Fitch. Easily distinguished from its five allies by its much smaller size. From S. brassicoides it is also distinguished at once by its always being solitary; from S. strobiloides by the tips of the leaves that lie "to the weather" being not rounded but angulated and beaked; from S. strobiliscus by the tips of the leaves being generally opened out and recurved, and always beaked; and from S. rhodoides and S. coryloides by all the leaves being sessile, instead of the terminal leaves, and in the latter case almost all the leaves, having peduncles. 

S rhodoides, n. sp.

On S. humilis

A monothalamous gall like an elongated rose, always growing singly on the tip of a twig, porrect, its general outline elongate-spherical, occasionally spherical and rarely short-spherical, .90 — 1.80 inch long and .70 — 1.90 inch in diameter, never with any twigs, however small, growing round it from the same stem. The leaves composing it are slightly pubescent, entire, with the midrib and branching side-veins very conspicuous, and are almost always opened out and with their tips recurved and occasionally at the extreme tip a little pinched together, but in a few cases they are loosely appressed except at the tip of the gall. The basal ones are small, the following ones larger, all sessile and heart-shaped with the basal lobes of the heart squarely truncate and the tip almost always taper-pointed in an angle of 70 — 80°; towards the tip the leaves become smaller and gradually more and more peduncled, till at the extreme tip the peduncle is generally twice as long as the leaf itself. Inside the gall the leaves suddenly become linear-lanceolate and gradually straighter as they approach the centre, till they finally embrace the lanceolate central cell precisely as in S. strobiloides. Sometimes the peduncled leaves at the tip protrude from the gall as the stamens and pistils of some flowers protrude from the corolla. 

Described from 15 galls freshly gathered in November, and 50 — 70 gathered in July. Very common in Rock Island County, Illinois. This gall arrives at its full size by the middle of July, when the outside leaves are externally palish green, often changing towards the tip of the gall to pale yellowish green slightly tinged with ro.sy and externally more or less glaucous. In the autumn the leaves become pale greenish brown with a slight whitish pubescence externally, and, after hanging on the twig over a year, almost black.

S coryloides n. sp.

On S discolor?

A very large and loosely expanded, monothalamous gall, resembling at a distance a bunch of hazelnuts in their natural husks, growing singly at the tip of a twig without any shoots surrounding it. porrect, its general outline spherical, sometimes elongate-spherical or short-spherical, 1.76 — -2. .35 inch long and 1.95 — 4.10 inch in diameter. The leaves composing it are on the outside large in proportion to the size of the gall, so that some of the middle ones are occasionally two inches across, free from pubescence except sometimes on their external base, entire, with the normal midrib and branching side-veins distinct, and are all of them very much opened out and recurved, the basal ones the most so, so that the latter often touch with their tips the twig on which the gall grows. The basal leaves are orbicular-ovate or ovate, only slightly smaller than the middle ones ; the middle ones are ovate, and both basal and middle ones have their tips tapering regularly in an angle of about 80° — 90°, not taper-pointed in an angle of 70° — 80° as is generally the case in S. rhodoides ; and their base describes an angle of about 90°, instead of being squarely and widely truncate, as in S. rhodoides, and even on the extreme base of the gall generally has a short peduncle nearly 1/8 as long as the leaf itself, which in each successive leaf gradually becomes longer as the tip of the gall is approached, when it is about equal in length to the leaf, which has now become oblanceolate. On the inside, the leaves suddenly become straight, porrect, and very much smaller, and are elongate-linear with their tips tapered to a very acute point, closely appressed, and gradually smaller, till they finally embrace the lanceolate central cell. In the autumn the leaves of this gall are dark reddish-brown, externally with a slight whitish bloom; at other seasons it is unknown to me. 

Described from 4 specimens. Very near S. rhodoides, which occurs on a totally different willow, but sufficiently distinguished by the characters specified in the description, as well as by its average size being just double. One of the above 4 galls had the heart eaten out by some lepidopterous larva; and adhering to the leaves of another was the pupal integument of a Lepidopteron, much larger than any of those commonly bred by me from the allied galls. All of them, as is very generally the case in this group of galls, had many of their leaves eaten into by Lepidoptera. and contained much Lepidopterous "frass" or excrement.

I know but three Willow-bushes near Rock Island which can be re- ferred to S. discolor. One of them, a $ . of which I forwarded to Mr. Bebb the inflorescence, was pronounced by him to be certainly S. discolor ; it was from this one that I obtained the galls, which for the present I refer to S. batatas and S. siliqua. Of the second, also a female, I forwarded nothing but the fruit, and Mr. Bebb referred it doubtingly to S. discolor, but thought it might possibly be S. eriocephala. I have carefully compared foliage, twig and bud in these two, and have little doubt they are identical. At all events their very robust, vigorous twigs, tinged with purple and covered with whitish pulveruiescence, so as strongly to recall those of many varieties of apple-tree, and the large buds which have commenced opening out even as early as the last of November, effectually distinguish both, even in the winter time, from the 4 other species of Willow found near Rock Island. The third bush was not discovered by me till the last of November, and agrees so perfectly in all the above characters with the one which is undoubtedly S. discolor, as well as in the foliage, some of which still adhered to its twigs, that I have little hesitation in referring it to the same species. I observed however on its main limbs large blotches or wide bands of whitish-gray, which could not be seen on either of the other bushes. In any case the inflorescence next spring will definitively decide the question of its specific identity with S. discolor. It was on this last that I found the galls C. coryloides ; the second bush bore no galls at all.

S. cornu

On S humilis

A lateral bud deformed into the shape of a monothalamous. very elongate, slender, cylindrical, tapering, hollow, rigid horn, very slightly pubescent, of a very dark reddish brown color when mature, and with about 12 or 14 longitudinal, pretty regular striae like a coleopterous elytrum. This gall is .30 — .77 inch long, .07 — .10 inch in diameter at base and .05 — .07 inch close to the tip. where for the length of about .10 inch it is flattened and moderately pubescent, and at the extreme tip, which is rounded, opens by a terminal slit. Sometimes it is solitary, sometimes 2 or 3 of them, or even as many as 10, grow at irregular intervals on a small twig 4 inches long, with a few of the intervening buds in their normal condition. Generally it is perfectly straight, diverging upwards from the twig at an angle of 15° — 35°, but occasionally it is a little bent in the middle, and occasionally it curves backwards in a regular curve, so that in one instance the tip nearly touches the base. When cut into, the walls of the hollow are seen to be no thicker than stout paper, but very stiff and hard, and on the terminal 1/2 the internal surface is pretty smooth with indistinct longitudinal rugae, except the terminal .05 inch, which is armed with very long, whitish pubescence directed obliquely forwards. In the basal 1/2 of the horn lies the cocoon, which is closely agglutinated to the walls of the cell except at its tip, where it forms a filmy, whitish diaphragm as in S. siliqua n. sp. ? The cell formed by the hollow of the de- formed bud is prolonged into the woody origin of the bud for .10 — .15 inch, but the twig itself is not swelled or deformed, as it is in the allied polythalamous gall S. triticoides n. sp., further than by a slight and scarcely noticeable intumescence at the origin of the bud. 

Described from 8 living specimens on four different twigs and 10 old dead and dry specimens all on one twig, the whole gathered in November. Out of the 18. 6 or 7 had been bored laterally by some minute parasite, and from at least two of the recent ones parasites had perhaps escaped at the terminal slit, for they contained neither larva nor cocoon, and were unbored, although one of the recent ones was bored. Rare near Rock Island, and difficult to discover from its simulating a short, lateral twig. When these galls occur in great numbers on a twig, the intervening buds perish, but when there are only one or two of them, they do not. When the twig is .08 inch or less in diameter, the part of it which lies beyond the galls shrivels up and perishes, even if there be only one of them, but when the diameter is .13 or over and there is but a single gall, it survives, at all events till the next season.

S siliqua n. sp.?=Salicis? Fitch=rigidae? Fitch, OS

On S humilis (and also on S cordata? and S discolor?)

A monothalamous, solitary, oval or subspherical. woody gall, .55 — 1.00 inch long and .20 — ..34 inch in diame- ter, growing at the tip of a twig, frequently with several twigs apparently of the same year's growth surrounding it, tt pared at tip to a short, blunt, tubiliform beak, which is evidently a deformation of the terminal bud, and hollow inside. The outside surface of the gall, which is the natural color and texture of the bark of the twig, always contains, besides the terminal beak-like bud, 2 — 5 buds, which are still alive in November in the recent gall but afterwards perish along with the gall itself, as does also, unless the twig on which the gall grows be large, a portion of that twig. Sometimes one of these external buds sprouts out into a twig, growing from the outer surface of the gall, and in a single spe- cimen there are four such twigs. The walls of the internal cell or hollow, in- cluding the bark, are .06 — .11 inch thick, and lined when mature inside with the cocoon of the gall-maker, which is detached and of the usual delicate texture towards the tip of the hollow, so as to form a kind of diaphragm to exclude any air that might enter through the terminal beak, but is agglutinated strongly to them everywhere else, though it may be detached piece-meal, generally with a thin layer of the greenish woody matter adhering to it. The internal surface of the terminal beak is smooth, continuous with that of the main c. 11 or hollow, and not strongly pubescent at tip as in <S'. cornu ; on its external surface there is the natural suture at its base. In one specimen, where a large, abnormal, woody wart had been formed about the middle of the hollow, the larva, instead of including the wart in his cocoon, had had the remarkable foresight to con- struct his cocoon entirely above the wart, and was thus compelled to make another diaphragm just above the wart, besides the usual one near the beak, and to lie in a much smaller compass than usual between the two. Described from 10 living- specimens and 27 old and dead ones, all from S. humilis. Rather rare near Rock Island. Varieties of S. ha- tatas n. sp. occur, which externally can scarcely be distinguished from «S'. siliqua ; but on cutting into them they are seen to be not hollow, but filled with a spongy substance containing several of the cells which are inhabited by the Cecidomyia of that polythalamous (xall; and more- over, the terminal bud is not beak-like and tubiliform. Specimens found on S. cordata in November differ as follows: — \st. The average dimensions are about i smaller, the length in 4 living spe- cimens and 41 dry and dead ones being .45 — .85 inch and the breadth .17 — .28 inch. 'Ind. Out of three of the living galls where the Ceci- domipa was present, there was in two a double diaphragm both at top and bottom of the hollow, instead of the single diaphragm at the top only; but in the other one the diaphragm was single and normal, 'ird. The number of buds on the external surface of the 45 galls is 1 — 3 in- stead of 2 — 5. \t]i. The terminal beak in i of the above 45 specimens is conspicuously recurved, whereas it is never recurved in those that grow on 8. humilis, thovigh it is sometimes a little oblique and in a single specimen is at right angles to the axis of the gall. A gall found August 1 had the beak so much recurved as to touch the side of it, like the tongue-case of the pupa of vSphinx 5-maculata Haw. — From my having in two successive seasons found the old dead and dry galls on both the above two willows at least 8 or 10 times as numerous as the green ones, and from the very weather-worn appearance of many of them, and the fact that a few of them were overgrown and almost obli- terated by the twigs that surrounded their base, I infer that they hang on the twig for several years. A single living gall gathered on S. discolor in November differed from the living ones found on S. humilis as follows: — Is^. The woody matter composing the outer shell is much thinner than in any one of 14 green specimens off S. humilis and 3 green specimens off S. cordata that I have cut into, being to a much greater extent medially interrupted by a layer of brown spongy matter, so that the gall was rather crushed by the knife than cut by it. 2.nd. Instead of the external surface being phimp and of the natural texture of the bark of the twig, it was strongly rugose, when recently gathered, and had much the color and texture of a completely withered blue plum. This does not occur in green specimens found at the same time of the year on the other two Willows, though it is often seen in the old dry ones. — Length 1.00 inch, diameter .80 inch, external buds 3. One specimen.

S triticoides, n. sp.

On S cordata [eriocephala?]

A polythalamous, woody gall .70 — 1.23 inch long and .30 — -.37 inch in diameter, bearing a remote resem- blance to a head of wheat with the kernels elongated, naked, pointed and very protuberant, its general outline oval or elongate-oval, and formed by the swelling of a twig to 2 or 3 times its former diameter, the swelled portion being very much contracted longitudinally, so as to bring each kernel-like bud nearlv or quite into contact with the base of the one that precedes it in the same row. the whole number being arranged in 4 irregular rows. Besides the swelling of the twig itself, the origin of each bud is also swelled into a more or less large tubercle, inside which is excavated longitudinally a cylindrical, slightly ru- gose and moderately polished cell, .25 — .27 inch long and .06 inch wide, the bud itself being elongated to about .17 inch and deformed so as to become a beak- like, tubiliform continuation of the cell, without any suture on the inside inter- vening, moderately polished inside like the woody part of the cell, and without pubescence as at the interior tip of the cell of 8. cornu n. sp. Through a slit at the tip of this beak-like bud the maker of the gall escapes, while, as usual, the parasite that preys on the gall-maker bores through it laterally. Above the gall the twig generally shrivels to about J its natural diameter, but occa- sionally where there are only a few cells — say 7 or 8 instead of 15 or 16 — it is not very materially diminished in size.— Described from 3 dead and dry speci- mens. Very rare near Rock Island. Larva, pupa and iMA(iO are all unknown; but from the structure of this gall being so exactly like that of *S'. siliqua n. sp. '( and espe- cially aS. cornu n. sp., there can be no doubt that it is. like those two galls, the work of a Cecidomijia . Inside several of the cells I found cocoons similar to those of C. s. strohiloldes. &c.. but much longer in proportion to their diameter, and not glued to the walls of the cell as in S. siltqua and *S'. cornu, so that I was able after relaxing the gall to extract two of them entire. They measured when extracted .42 — .44 inch in length and .06 inch in diameter, thus occupying the entire length and breadth of the cell including the beak formed by the bud. In the bottom of many of these cells, where the beak-like bud was bored laterally, I found an empty cocoon very similar to that of a parasitic Proctotrupide which occurs in the imago state in November in the central cell of aS^. strohiloides O. S. ; and in these cells there was no Cecidomyidous cocoon, as is also sometimes the case in the cells of C. s. strohiloidea that are occupied by the above Proctotrupide. 

S hordeoides n. sp

On S humilis

This gall has some resemblance to a beardless ear of four-rowed barley, and differs as follows from S. triticoides : — 1st. The twig on which the cells are placed is not materially enlarged and is of a uniform diameter throughout. ^Ind. The twig is abnormally shortened as in S. triticoides, but only so that the tip of each deformed bud touches or nearly touches the base of the one that succeeds it in the adjoining row. instead of the base of the one in the same row. 3rr7. The entire cells ai*e only .20 inch long, instead of .42 — .44 inch, and they extend only .05 inch, or \ of their entire length instead of 3-5ths of their entire length, into the woody origin of the bud, the deformed buds being not much elongated, but hollow and. as well as the woody part of the cell, polished internally. Ath. The woody origin of the buds is scarcely swelled and protuberant. — Described from one dead and dry specimen, 1.40 inch long and .10 inch in diameter. It contains 10 deformed buds, regularly arranged with no undeformed ones intervening, as is the case in the monothalamous gall S. cornu, when several of them grow near each other. As in some S. triticoides. the tip of the twig has completely shrivelled up and per- ished. Easily distinguished from the monothalamous, Tenthredinidous gall, S. gemma n. sp., which occurs on the same Willow, by there being no normal buds between the affected buds, and by the buds themselves not being abnormally swelled out laterally, and being hollow, not solid, inside. But for the fact of several of the deformed buds having been bored by minute parasites, I should never have suspected this specimen of being what it most undoubtedly is — a true Cecidomyidous gall ; and but for its strong homologies with S. triticoides. I should hesitate whether to consider it as a congeries of solitary galls, like aS'. cornu. or a true polythalamous gall, where the twig itself is swelled and deformed and converted into a gall, like S. triticoides. It must be very difficult of discovery, when it is recent and the cells are unbored by any parasites. Larva, pupa and imago unknown.

S nodulus, n. sp.

On S longifolia [interior]

A small, monothalamous, woody gall, sometimes terminal but generally not so, scarcely ever including any buds, growing on twigs .05^.15 inch in diameter, variable in shape, but generally consisting of a mere oval enlargement of the twig to half as large as its normal size for the length of .20 — .50 inch. The surface of the enlargement is either the usual color of the bark, or simply discolored and dark, or a little roughened with brown scales and longitudinally sinuate and interlacing stria. Occasionally it assumes the form of an elongate, lateral, bunnion-like swelling about .27 inch long and .1.3 inch wide, as in some varieties of S. batatas n, sp., and in one specimen there occurred an intermediate grade between this variety and the normal type; occasionally it grows at the base of a very small side- shoot, when the tip of the side-shoot shrivels up and perishes ; and occasion- ally the growth of the side-shoot is completely arrested, and the gall becomes a mere obhemispherical swelling about .20 inch in diameter, with its upper sur- face in an irregular plane, and very rugose and brown, located at the spot where normally there ought to be a bud. On cutting into this gall in Novem- ber, it is found to contain a single cell — smooth on the inside when the gall- making larva is present, but, as in ^S". batatas, without any separate cocoon — and much reddish-brown matter where the larva had formerly burrowed, and occa- sionally some grass-green soft matter: but the external walls are still in their normal white, ligneous state, the larva having apparently confined itself to the pith and the wood immediately surrounding the pith. Described from 9 specimens. Rare uear Rock Island. Externally this gall cannot be distinguished from the smaller varieties of C. bata- tas, but the former is monothalamous, the latter polythalamous ; neither can it be distinguished, except by its much smaller size and its much smaller cell, from the Tenthredinidous gall G. nodus which grows on the same willow. Of the 9 galls examined, 7 were unbored, 3 of which contained each a single larva of Oec. s. nodulus, 1 a single hairy Chalcididous larva, probably a Callimome, 1 a single Curculionidous larva, no doubt an Inquiline. and in 2 the gall-making larva was absent and must have perished in early life, for although its work was plainly visible yet the gall was not bored. In none of the 9, whether bored or un- bored, had the twig been killed, except in the very small gall before referred to, where the terminal bud had sprouted out into a minute shoot which afterwards perished. The smallness of this larva and there being only one in each gall, readily account for this otherwise anoma- lous fact. I found Dec. 1st in one of these galls, which had been bored by a single hole and contained no Cecidomyidous larva, a minute Lepidop- terous larva, doubtless an inquiline, and over a dozen small and young Aphis, which had probably taken refuge there for the winter. May not Hartig have been deceived by some such case as this into suppos-ing, that certain European Willow-galls were the work of Aphis ? (See above, p. 551.) On July 31st I found a bored and empty specimen of the Tenthredinidous gall C. pomum tenanted in the same manner by over a dozen Aphis.

S batatus n. sp.

On S humilis (S cordata? and S discolor?)

A polythalamous gall of very variable shape and size, pale green when young, the color of the bark when mature, growing on twigs .06 — .19 inch in diameter, almost always some distance from the tip of the twig. Sometimes it resembles a small kidney-potato pierced lengthways by a twig, and has then most generally a smooth, polished surface studded with a few buds, one or two of which occasionally give birth to a shoot, and it then reaches 1.35 inch in length and .60 inch in diameter. Sometimes it resembles a young apple pierced lengthways by a twig, and it then attains a diameter of .50 inch. Sometimes it forms a hemispherical or hemielliptic swelling, like a bunnion, on the side of the twig and attains a diameter of .30 inch. Sometimes all these different shapes are strung together one after the other in more or less close proximity, on the same twig. Sometimes it is reduced to a small, elongate-oval enlargement of the twig for 1/2 or 3/4 an inch ; and occasionally it becomes so irregular and so full of side-shoots, bulges, cracks, roughnesses and lobes, as to defy description. Very rarely it is terminal and assumes the form of S. siliqua, but may be distinguished by the terminal bud not being elongated and tubiliform, and by being solid and not hollow inside. On one occasion I found what had evidently been a S. siliqua gall, occupied laterally by spongy matter containing 4 larvae undistinguishable from those of C. s. batatas, the elongated cell of the larva of C. s. siliqua being still in existence but contracted in diameter and empty. When these galls assume the elongate bunnion-like form, they are undistinguishable externally from the Tenthredinidous gall S. ovum, which occurs on S. cordata. and S. ovulum, which occurs on the same willow as S. batatas, but may be distinguished on cutting into them by the fibres being linear and radiating from the twig, whereas the other two galls are composed of a series of spongy lamellae at right angles to the axis of the twig, and moreover, when laid open to their base, ex-hibit the longitudinal slit made by the ovipositor of the mother Saw-fly. The smallest galls above referred to are only .15 inch in diameter; but there is a regular gradation from these to the larger and more conspicuous forms, and by isolating a number of the first in a separate breeding-jar, I ascertained that they produced the same Cecidomyia (7 specimens April 7 - May 10) and the same 3 parasites, viz. 2 Chaleidides and 1 Proctotrupide. When cut into about the last of July, the interior of this gall to the depth of .07 — .10 inch from the surface, is found to be white and fleshy; when cut into in the autumn or early in the spring, the substance of all but the very smallest, which are almost entirely woody and whitish, is found to be reddish-brown and of a dense, spongy texture, with indistinct fibres radiating from the twig. Some little distance from the external surface there are at this time a number of cells, about § of them tenanted by white, parasitic larvae, some hairy and some glabrous, be- longing to the Chalcididous genera Callimome and Decatoma (?), and about J of them tenanted by the orange-colored larvse of the Gall-gnat which originates the gall. In 3 or 4 instances I have seen the gall S. gnaphalioides growing sessile from the tip of (S. batatas. — Described from 100 — 150 specimens. Very com- mon near Eock Island on S. humilis. In galls similar to the last mentioned, small, elongate-oval galls, but growing on S. cordata. I found May 9 a larva undistinguish;ible from that of C. s. batatas and with the same breast-bone, but did not suc- ceed in breeding the perfect Grall-gnat. though I obtained many Chal- cidiffpe from these galls identical with two species bred copiously from S. batatas, one of which — a Decatoma ('^) with spotted wings — has hitherto occurred in no other gall, though a similar species infests Ci/- nips q. spongifica and other gall-flies. In November I found on *S'. discolor 8 galls, apparently identical both externally and internally with the iS. batatas found on S. humilis, 8 old and dry ones of the normal form which were all bored and strung along on the same twig, and 5 green and recent ones of the lateral, bunnion-like type on two diffbrent twigs. Their diameter was .19 — .40 inch. From the recent ones I obtained 6 larvae, which when compared with 6 taken from galls on S. humilis differed in no respect. In the preceding spring I had obtained 2 or 3 similar galls of the bunnion-like type from the same bush, from which I bred a large Microijaster, whence I infer that some lepidopterous larva had been living as an Inquiline in one of them, as the parasite was much too large to have lived in the body of C. s. batatas, and besides I have met with no instance of Ich- neumonidous insects being parasitic on Cecidomyia. I found at the same time several galls on the same bush, which, as has been stated to be sometimes the case in >S^. batatas, assumed the form of a slight, elongate-oval enlargement of the twig; but from these I bred nothing. < )n the whole, further investigation will be required to determine, whe- ther tbe imago produced from these galls on S. cordata and S. discolor is identical with Cec. s. batatas. It is rather singular, that in these »S. discolor galls I found no larvae at all of the Decatoma (?) and Calli- mome, which so greatly outnumber the larvae of C. s. batatas in the S. humilis galls. It is worth remarking, that the only two Cecidomyidous galls which appear to grow on more than one species of our Rock Island Willows — viz. aS'. batatas and C. siliqua — occur on as many as three species of them, and that these three species should in both eases be the samf", three, viz. S. humilis, S. cordata and S. discolor. The chances are very greatly against such an event happening, without some good and suffi- cient cause for it. Mr. Bebb informs me that there is a close alliance between S. humilis and S. discolor; but that neither S. cordata (=S. rigida) nor S. lucida is allied to the first two. While on this subject I may say that Mr. Bebb has re-examined the doubtful species of Wil- low referred to above (p. 546), and has concluded that it is certainly neither 8. nigra nor S. alba, and that it is not improbably S. fragilLs Lin., a species which has been introduced into N. A. from Europe. 

S verruca, n. sp. 

On S humilis.

A small, monothalamous, irregularly spherical, greenish yellow gall, .07 — .13 inch in diameter, growing the latter end of August from the midrib or some of the principal veins of the leaf, half of it projecting from each side of the leaf. The upper side is flattish or with a minute point or nipple, the lower side branches out into a ragged, wart-like excrescence, whence the specific name, which later in the season bursts open so as to afford an exit to the insect. When cut into in August, the external wall of a few galls is found to be rather woody, enclosing a central cell, in which lies the larva; but the majority of them-are still solid. From 1 to 12 are found on a single leaf, several of them being often confluent, but with their internal cells, when they have any, separated by a thin partition, and with separate warts to each on the under side of the leaf, which afterwards open separately. 

Rather abundant, but local near Rock Island. Described from 38 affected leaves. 

S semen, n. sp.

On Salix nigra

A minute, monothalamous, hollow, irregularly hemispherical, greenish yellow gall, .02 — .04 inch in diameter, mostly on the upper side of the leaf, and often, but not always, with a pointed nipple on the middle of the hemisphere, always with a corresponding circular depression on the other side of the leaf, in the middle of which is a very minute, flattish hemisphere. Very frequently on one and the same leaf the position of the gall is reversed from the ujjper to the lower side, as in Q. pihiloe Walsh. On a single leaf scores of them may often be counted, generally with several masses among them, composed of two or more confluent galls. Commences its growth early in the summer, and by the last of August many are found to be burst open at top, yet at the same time very many of them, when opened, are found to be solid without any central cell. By November most of the galls from which I attempted to breed the insect had burst open into a ragged, wart- like shape on the hemisjiherical side, but no larvte had escaped from them and none were discoverable in them. As the leaves were kept too moist, so that they moulded badly, the larvae had probably perished in the galls. Described from 20 affected leaves. From its close homology with the much larger oak-galls St/mmrtrk-a 0. S. aqd Q. pilulse Walsh, iu the former of which Cecidomyidous larvae were detected by Osteu Sacken, and described (Dipt. X. A. p. 201) as having a Y-shaped breast- bone, and in the latter of which I found myself, September 14th, several orange-colored larvje, which, from the presence of a clove-shaped breast-bone, were undoubtedly Cecidomyidous, and from the fact of a similar leaf-gall on a Willow, *S'. verruca n. sp., being inhabited by a Cecidomyidous larva, there can be no doubt, I think, that the gall S- semen is the work of a Grall-gnat. Prodigiously abundant and very common everywhere in Rock Island County, Illinois, on the Black Willow, the foliage of whole trees being thickly frosted over by it, so that the leaves look like nutmeg-graters. I have in a cursory manner noticed in July several specimens of what seemed a very similar gall ou S. discolor, but found no larva) in them ; and in a single instcince I found, August 20, two leaves of S. longifolia on a twig which grew out of a bunch of the galls S. brassicoides, covered so densely with some- what similar galls as to be intermediate in appearance between S. se- men and *S'. penigma. On August 29 I discovered in one of the cells of this gall a minute, pale-colored, apod larva with a large, scaly head, and the disk of its dorsum, but not of its venter, fuscous. This so ex- actly resembled a much larger larva of which I have found many spe- cimens in the Cecidomyidous gall, Q. pilidx Walsh, and which I am sure, from comparing it with the larva of Anthonomus scutellatus Schonh., must be Curculionidous, that I believe it to be also Curculionidous, and inquilinous, like the othei* larva, iu the gall where it occurred. I have noticed towards the last of August galls about the size of the head of a large pin. similar to S. semen, and often similarly confluent, o'rowino- in con.siderable abundance on the leaves of the River Kirch (Betula nigra), chiefly or almost entirely on their upper surface. And on the leaves of the Button-bush (Cephalanthus) I have noticed at the same period of the year galls of the same character, in the same luxuriant profusion as S. semen occurs on the Black Willow, whole bushes being covered with them ; but in neither of the two kinds could I discover any larvae. I believe them both to be the work of Cecidomyia. It does not follow, because all these galls are so small, that therefore their Gall-gnats must be abnormally small. The gall S. rhodoides n. sp. is about 4 times as long and wide as the Grail S. gnaphalioides n. sp., yet the Gall-gnat produced from the latter is only \ shorter than the (rail-gnat produced from the former. Larva, pupa and imago unknown. 

S aenigma, n. sp.

On S nigra

A polythalamous, crumpled, irregularly spherical or ellipsoidal mass, something like the aborted mass of flower-buds of a common cauliflower, but with a more ragged and uneven surface, .30 — 1.10 inch in diameter, and growing almost sessile or sometimes on a stem as long as .50 inch, which is often branched and much flattened or distorted, from the side or occasionally from the tip of twigs .05 —.30 inch in diameter. When cut into early in the summer, there is seen to be no regular heart or symmetrical arrangement of the parts, as there is in all monothalamous galls, and the stem is crisp and rather fleshy than woody. This gall first appears early in June, being chiefly a deformation of the flower-catkins, but occasionally, unless I was deceived from confounding it with S. semen n. sp., which I think must have been the case, of the leaves. At that time, and for a month or two afterwards, it is of a pale green, but long before autumn it dries up and becomes brittle and of a dark ash-gray color, without, however, losing its original shape, and hangs on the trees till long after the next spring opens. It contains, so far as I could discover, no regular cells, but the larvae of the Gall-gnat appear to burrow irregularly in the main stem and its branches. On the same twig may often be seen 6 or 8 of these galls at irregular intervals of half an inch or U inches, and frequently two of them grow side by side and run together. "Whole trees are sometimes so covered by them, that the galls seem almost half as numerous as the leaves. As usual, the twigs, unless very large, are killed by the presence of these galls shortly after the galls have become mature. 

Described from 150 — 200 specimens. Very common and abundant everywhere in Rock Island County, Illinois. 

Amphibolips prunus [new name]

I found last August and early in September, in very great numbers both on Q. rubra and Q. tinctoria, growing on the side of the cup of the acorn, a globular, smooth, plum-like, fleshy, intensely bitter gall, about .50-.75 inch in diameter, mottled with yellowish and crimson outside, and internally yellowish in the centre and towards the circumference pink like a watermelon. This gall, of which I forwarded a specimen to Baron Osten Sacken, is thought by him to be identical with his Q. juglans, which was described only from dry, shrivelled-up specimens, and which was stated by Mr. Hitz who found it "to grow on the branches of the White Oak," (Q. alba.) a species that belongs to the first section of Quercus. Either Mr. Hitz must have been mistaken, both as to the tree and the part of the tree on which he found Q. juglans O. S., or else my gall is a distinct species. If so, I propose for it the name of Q. prunus. It is the only N. A. Cynipidous gall known so far to grow on the acorn, though, judging from the names, the European Cynipidous galls, q. calicis and q. baccarum, grow the one on the cup of the acorn, like Q. prunus, and the other on the acorn itself.

On the Insects, Coleopterous, Hymenopterous & Dipterous: Inhabiting the Galls of Certain Species of Willow. Pt 1st--Diptera