Phylloxera caryaesepta

Phylloxera caryaesepta (perforans)

Phylloxera caryaefoliae

Phylloxera picta

Phylloxera intermedia

Phylloxera foveola

Phylloxera pilosula

Phylloxera deplanata

Phylloxera depressa

Phylloxera foveata

Phylloxera minima

Phylloxera caryaesemen

Phylloxera caryaefallax

Phylloxera rimosalis

Phylloxera caryaescissa

Phylloxera caryaeglobuli

Phylloxera conica

Phylloxera caryaeavellana

Phylloxera symmetrica

Phylloxera notabilis

Phylloxera globosa

Phylloxera caryaegummosa

Phylloxera caryaevenae

Phylloxera caryaemagna

Phylloxera spinosa

Phylloxera caryaecaulis

Phylloxera spinuloides

Phylloxera devastatrix

Phylloxera georgiana

Phylloxera subelliptica

Phylloxera perniciosa

Phylloxera caryaeren

Phyhoxera caryae-septum (Shimer). 

Dactylosphaera c.-septum  
Phylloxera c.-septa  

The galls of this species, especially those of the more typical form, are the handsomest and largest of this group. Their transverse diameter at the plane of the leaf ranges from 5 to 12 mm and their vertical diameter from 4 to 6 mm. They are quite convex on both sides and generally more conical and more prominently projecting above than beneath, especially so in the smaller specimens. All are provided with a nipple on both sides, the upper one stouter and more prominent, with its base more or less sunken below the plane of the gall. Both nipples, particularly the lower one, lean frequently somewhat towards one side. Both openings are either round or oval and fringed by about eight stout or slender filaments. The opening on the under side closes gradually so that the insects are compelled to leave from above. The consistency of the galls is dense, though rather thin, paper-like, and more or less transparent, crisp, and stoutest at the junction with the leaf. The cavity, if cut vertically, appears to be more or less hexagonal at the central portion, more or less pointed towards the nipples, and quite flat at the median circumference, with the exception of a ridge which indicates the former division of the gall into two compartments while young. The color above is variable. Some are of a darker or lighter bright red or pale rose, with a pale greenish margin around the base, while others are pale yellowish green, the nipple more or less brown, surrounded at base by a pale reddish ring. The color of the under side corresponds either more or less with that of the upper side or is of the same color as the leaf, or paler. In its younger stage, while still quite small, it is most beautiful and has very little resemblance to the fully grown gall. 

The first observations regarding this gall were made May 13, 1883, and, as it will help to throw some light on the question of the formation of this and many other galls, I will here include the few notes made at the time. This gall, a very beautiful and curious object, I find, after a careful examination, to be nothing else but an abnormally great enlargement of a pore and the filaments or hairs surrounding same. From the position of the galls, there can be no doubt whatever but that the young insect, as soon as it finds a suitable place, stations itself directly over a pore on the under side of a young leaf, into which it inserts its proboscis to extract the sap and to remain in this position. The irritation, caused by the sucking, gradually enlarges the pore so that the insect can sink into the opening; the rapid growing of the leaf causes the walls of the pore to prolong and the thus formed cell to widen till a regular cell is formed, enclosing the insect completely. 

Remarkable it is, however, that the irritation is not confined to the lower side of the leaf but that it extends also to the upper surface, to the opposite pore, producing a counterpart of that on the underside. Both sides of the young gall at this stage are regularly conical and are fringed at the apex of each cone by about eight or nine very long, slender, backward curved, fleshy filaments which, when compared with the hairs surrounding the other pores, prove them to be identical though greatly enlarged. When some of the galls were opened it was found that they were divided horizontally by a delicate membrane into two compartments in the lower one of which the young stem-mother, already mature at this date, and surrounded by some eggs, had established her home. With her was also found but one cast skin, which seemed to indicate that several skins had been cast before the gall had formed and closed. The color of the young gall above is quite pale green with the filaments bright cherry or pink. The lower side is darker and the filaments white. Two weeks later the galls had changed so completely in appearance that they could scarcely be recognized as belonging to the same species were it not for the filaments fringing the apex of the nipples, and even these were mere rudiments, much reduced by drying up. They were then fully mature and some of them already empty. When cut vertically it was observed that the dividing membrane had entirely disappeared, except the before- mentioned rudiment at the circumference. 

Phylloxera caryae-septum, var. perforans n. var.

A very conspicuous form of [the above gall](https://www.gallformers.org/gall/2876) has been occasionally observed in the vicinity of Washington for several years past, occurring usually upon the leaves of Hicoria glabra, though always when already deserted. This same form had previously been observed by Dr. A. Fitch in the state of New York, also when deserted. 

During May of 1890 1 have been fortunate, however, to discover this form in fair abundance upon a single tree of Hicoria glabra growing near a small stream in the vicinity of Arlington, Virginia, and widely separated by hills and gullies from trees bearing the genuine or typical gall. They contained (May 16th) besides the other forms a considerable number of the winged migrants which proved, after careful examination and comparison, to be absolutely identical with those of Ph. c. -septum. The causes of this remarkable and constant variation are not readily explained except by the fact that the typical form has so far always been found upon young trees with large and succulent leaves of Hicoria alba [Carya tomentosa], while those of perforans were upon trees of Hicoria glabra [Carya glabra] which had already attained a height of over twenty feet and with the leaves smaller and less succulent. As in the typical form, the gall is mostly single though now and then two, three or even more grow in close contact, generally close to the midrib, near its base, or near the stronger, cross-ribs, and, instead of expanding horizontally, they become narrow and considerably elongated above and beneath, resembling a slender spur or nail forced through the leaf. The length of the cones varies from 3-8 mm and the diameter at base from 2-4 mm. Both above and beneath, the cones usually lean to one side, those above usually in the opposite direction from those beneath, while cones growing near the edge of the leaf curve outwardly and often to such a degree that both points almost meet. Each cone splits into 6-8 slender bracts, fitting closely together and lined inside with a white, woolly pubescense. 

At maturity the bracts of the upper cone separate to allow the insects to escape, while those on the under side remain closed. The inner structure of the galls is very similar to that of the typical form, though its walls are harder and thicker. Its color above and beneath is of a paler green than the surrounding leaf, incling toward the apex to purple or brown. The transverse ribs between which these galls are stationed are, at the point of junction, often considerably angulated, much thickened and of a beautiful red or crimson color. 

Phylloxera caryaefoliae

Notwithstanding the apparently wide distribution of this species from New York to Illinois and as far south as Washington, it appears to be nowhere so common or so destructive as some of its near relatives. It is most noticeable during the latter part of May on the leaves of Hicoria glabra, and though usually there is but a single gall upon a leaf, as many as four may sometimes be found. Some which were studied on the 23d of May along the Potomac River in Virginia contained already quite a number of winged migrants, though the gall had not yet sufficiently opened at the apex to allow the inmates to escape. 

The principal part of the gall is always on the upper side of the leaf and represents a regular, slender cone which often leans slightly over to one side. The transverse diameter of the gall at the base of the cone is about 3 mm and, including the pale ring surrounding it, about 5 mm; and its vertical diameter is also about 5 mm. Its surface is more or less pubescent, more densely so beyond the middle. Its color above is pale green, with numerous still paler, extremely fine, radiating lines running from tip to base. The apex is either somewhat somewhat yellowish, pale brownish or pale purplish and the extreme base darker green. The ring surrounding its base is either somewhat projecting and slightly convex or sometimes depressed or saucer-like and of a yellow or greenish-yellow color. The under side of the gall is but slightly projecting and quite flat, with a small elevated ring surrounding a minute central depression from which rises a small nipple, splitting into a number of very fine and slender pubescent filaments. The walls of this gall are very thin and flexible and rather difficult to tear, especially when they commence to shrivel after having been taken off the tree for some time. They are stoutest at base and more or less transparent if held towards the light. That this species is closely related to Ph. c.-septum is quite apparent. The younger ones have also, as in that species, a transverse membrane which gradually disappears, leaving a distinct rim to indicate its position.

Phylloxera picta Pergande, n. sp. 

The galls of this species resemble very much those of c.-septum, though ordinarily smaller, much more flattened, and to all appearances entirely destitute of a dividing membrane. The insects are also smaller and paler and exhibit some characters which tend to separate it from that species. The transverse diameter of the gall varies between 3-6 mm and the vertical diameter between 2-3 mm. It is quite flat on both sides, though somewhat more elevated and more convex on the upper, with a more or less distinctly depressed ring surrounding the base of the nipple. Both sides of the gall are provided with a short, conical nipple, each closed till maturity, and furnished inside and generally also at the tip with fine pale hairs. The lower nipple always remains closed, while the upper opens in a round or oval mouth, split into several very short, recurved bracts covered with fine pubescence. The walls of this gall are very thin and semi-transparent so that the insects can be seen moving about if held towards the light. The color is variable. Some are quite dark-green with a faint purplish shade and with the nipple and a ring around its base dark red. Others are of the color of the leaf or slightly paler, with a faint purplish ring surrounding them, the nipple and the depression surrounding its base pale buff or pale clay-yellow. Another variety is more or less pink, its margin yellowish or concolorous with the leaf. Still others are pale greenish-yellow with a faint purple ring surrounding the still darker nipple, besides many other variations. The under side is uniformly paler than the leaf and the nipple yellowish. 

It occurs on Hicoria tomentosa and matures by the end of May or early June. 

To separate this gall from many of the forms of Ph. intermedia is often very difficult, especially after they have burst open, when they resemble each other quite closely, though a comparison of the winged forms of both will show them to be unmistakably good species. 

Phylloxera intermedia Pergande, n. sp. 

The gall of this species appears to be intermediate between Ph. c. -septum and Ph. picta. Its inner construction resembles that of c. -septum on account of the presence of a rudiment of the central membrane, though its general form, especially in the larger specimens, is more like that of picta, from which, however, it differs in the much thicker walls and the absence of a nipple on the upper side. 

The transverse diameter of this gall varies between 3 and 6 mm and its vertical diameter between 2 and 3 mm. The shape above is regularly convex in the larger galls and slightly conical in the smaller ones, and without a trace of a nipple or opening before maturity. On the under side it projects but slightly and is provided with a minute, but closed nipple, the insect issuing from the upper surface which splits in a more or less jagged, round or oval opening, the bracts of which curve more or less outward. In some few cases the nipple on the under side also opens sufficiently to allow the insects to emerge from both sides. The color of the galls above is reddish or yellowish, generally surrounded by a paler ring, and beneath paler than the leaf. It occurs on Hicoria alba [Carya tomentosa] in company with the other two, and matures from the end of May to the middle of June. 

Phylloxera foveola Pergande, n. sp. 

The gall of this beautiful species is evidently closely related to and may possibly be identical with Ph. foveata Shimer, but considering the number of closely allied species in which the galls resemble each other more or less closely, and the fact that the inmates of his galls were winged and plentiful by the 20th of June at Mt. Carroll, IL., whereas the galls of foveola are nearly deserted by the 1st of June, near Washington, induce me to consider the two forms as specifically different. 

I have found this gall during the latter part of May upon Hicoria glabra in the vicinity of a small creek between Arlington, Va., and the Potomac River. Most of the galls contained, as early as May 23rd, numbers of the winged form. These galls grew either singly or as many as forty upon a single leaf when they become at times confluent, each retaining, however, its char- acter and individual cell intact. On some of the trees they were much more numerous, completely covering some of the leaves. The diameter of the galls ranges more or less between 3-5 mm hor- izontally and between 1-3 mm vertically. They are as a rule very convex and more prominent above than beneath, with a rather deep dimple or depression at the centre, which depression occasionally reaches as far down as to the opposite side of the gall; its basal circumference forms either a depressed or elevated ring. Beneath they are but slightly convex, often sunken below the plane of the leaf, with the centre depressed and bearing a very short, somewhat conical nipple, which is tightly closed and densely covered on the inside with a pale pubescence in the younger galls, whereas in the older or mature galls the nipple splits into 4-8, or rarely more, short and rather flat recurved bracts, which leave a round or slightly oval orifice between them. 

In the largest and perfectly developed galls the upper side is either of a delicate pale red with the dimple darker and its basal circumference yellowish-green ; or entirely yellowish-green with only the dimple of a beautiful pink color. Beneath they are uniformly yellowish-green, often with a faint reddish tinge, especially toward the nipple. On the other trees, most densely covered by them, they were less beautiful, with less red and a shallower dimple. The walls are very thin and paper-like and readily collapse when old. All galls are perfectly smooth on both sides. 

Phylloxera pilosula Pergande, n. sp. 

The galls of this species are very unique and readily distinguished from any others so far observed. They occur usually on solitary trees of Hicoria glabra along the Potomac near Washington. They are usually quite abundant though rather sparsely distributed, there being but one, or rarely more than 3-6, upon a leaf and seldom so close together as to become confluent. 

When first found, May 23rd, they were already fully developed, but contained, besides the stem-mother, only eggs and larvae. Ten days later most of the insects had already acquired wings. The transverse diameter of the gall varies between 3-6 mm, and their height to the tip of the nipple 2-3 mm. They are quite flat above, even with the surface of the leaf or but slightly projecting above it. In the latter case they are usually surrounded by a somewhat depressed ring and have a slight inclination to one side. There is always a more or less distinct shallow depression at the middle, which is usually quite densely covered with rather long, faintly yellowish, soft and glistening hairs. On the under side they resemble somewhat those of the variety Ph. c. -symmetrica, though they are more evenly convex and provided with a rather long and slender nipple, which is split into five to six, or rarely more, slender filaments, which usually lean to one side. This nipple, as well as the surface of the gall, is quite densely covered with long, glistening and faintly yellowish hairs similar to those on the upper surface. This pilosity of the gall is quite in contrast with the otherwise perfect smoothness of the leaves above and beneath. The upper side of the galls is of a paler green than the leaf itself, with a slight tinge of yellow, whilst on the underside the color merges gradually from pale green at its circumference to almost white at the nipple. The walls are quite solid and rather stout at the base. The galls are almost per- fectly white on the inside and semi-transparent. 

 Phylloxera deplanata Pergande, n. sp. 

The galls of this species and their architects were carefully studied in 1883 on some small trees of Hicoria tomentosa growing on a hilly slope, bordering the Potomac River, opposite Georgetown, D. C. An interesting fact connected with the species was the absence of the winged or migratory generation, in which respect it agrees with Ph. c. -semen Walsh and PA. caryae-venae Fitch. That Ph. deplanata is distinct from this last is made patent by a comparison of the galls and stem-mother ; while it would also seem to be distinct from Ph. c. -semen, its western representative. The galls of Ph. c. -semen are the smallest known, measuring not more than 0.6-2 mm horizontally, being more or less subglobular and provided with a round orifice, surrounded by a fringe of 5-8 or more, rather broad bracts; whereas the galls of this species have a transverse diameter of 1-5 mm, are but slightly convex above and more prominent beneath ; the orifice is oval and without any bracts, but closely fringed with fine hairs. Its walls are rather thin and flexible, while those of Ph. c. -semen are thick and hard. In how far the insects of these two galls differ is not at present known, but there is little doubt that future more careful study of Walsh's species will reveal sufficient differences. 

The leaves of some of the smaller trees are often literally covered with the galls of deplanata which then produce a sickly, yellowish and crumpled appearance thereof. By the end of June the galls are deserted, brown and dry, or else have completely decayed, leaving innumerable holes in the affected leaves, seriously affecting the health of the tree. When but a few days old (first week in May) these galls resemble minute yellow specks. 

The transverse diameter of the mature galls varies from 1-5 mm; height about 1 mm; walls rather thin above and beneath and semi- transparent. Upper surface projecting but little above the plane of the leaf, convex, usually with a shallow fovea ; frequently not central and occasionally with a slight central elevation. Under side more strongly convex, sometimes almost conical, the nipple usually more or less flattened and generally leaning to one side, as if pressed down when young; with the orifice usually oval, though sometimes more or less rounded, and which before maturity is perfectly closed and densely fringed with short pale hairs. Color above either reddish with the depression yellowish, or almost entirely greenish -yellow ; below purplish or dull greenish-yellow. Many of the galls are conjoint, i. e., contain from 2-6 or more stem-mothers together with large numbers of eggs and sexual individuals, the cavity being completely crowded. 

Phylloxera depressa. Shimer. 

Dactylosphaera depressum Shimer. 

Not having had an opportunity of seeing this gall, I am unable to form an opinion as to its specific value and reproduce, therefore, the description as given by Shimer: 

"These galls were found to be exceedingly numerous on some trees (Carya alba [Carya tomentosa]). On June 20th they were smooth, slightly rounded above, pale yellowish-green; beneath somewhat whiter, and having in the centre a nipple-like projection ; opening round, surrounded with a burr-like fringe composed of many filaments, the cavity like an inverted cone, the wall above being quite thin and translucent, so that the inmates may be seen moving about. This apparently very flat gall was placed as much below as above the plane of the leaf. Diameter .15-. 25 inch [3.8-6.2 mm]; vertical thickness .125 inch [3 mm]. " 

Phylloxera foveata Shimer. 

Dactylosphaera foveatum
Phylloxera forcata

This appears to be nearest related to Ph. foveola n. sp. and Ph. intermedia n. sp., though as no opportunity has offered to further study foveatum at Washington, Shimer' s original description is reproduced: 

"On the same leaves [of Carya amara] containing the small galls, Nos. 7 [Ph. minimum Shimer] and 8 [Ph. c. -semen Walsh] , I observed a number of larger ones with a dimpled depression above (which may be caused by the collapse of the thin paper- like centre), an opening beneath by a rounded, downy orifice, and having a diameter of .06-. 33 inch [1.5 mm] and a vertical depth of .12-. 16 inch [3-4 mm] ; all contained the female and her eggs, and some larvae."

Phylloxera minimum Shimer. 

Dactylosphaera minimum

Shimer' s original description is as follows: 

"Small round galls, generally very numerous in the leaves, and in some cases almost entirely covering them, a single leaf sometimes containing upwards of 250 galls; the average size -larger than those of No. 8 [Ph. foveatum Shimer], although often quite as small, the larger ones measuring three-sixteenths of an inch [5 mm.] in diameter. They were (June 25th) quite hard and smooth, and present, especially above, a bright, shining appear- ance; they were quite thick and plump, the vertical diameter compared with the horizontal diameter being as 2 to 3, and were much more plump and elevated above the leaf than those of No. 8 [Ph. carya-semen Walsh]. The portions of the leaf between the galls had in some cases turned crimson. I found from three to twenty-five inhabitants in a gall; the round opening beneath was so close as to be pretty safe against enemies, as I found none in the galls opened thus far. larvae and pupae whitish, with red eyes; mother insect cinnamon color and smaller than the pupa. 

"On July 5th I found winged imagos in all the galls, large and small, that were opened, the smallest galls not much exceeding .05 inch [1 mm] in diameter; when opened, the young insects eagerly ran out, and all presented the same pale, translucent appearance, with minute dark spots on the anterior part of the body, which is in contrast with the inhabitants of gall No. 8. The winged imago was first observed on June 30th."

Phylloxera caryae-semen Walsh.

Phylloxera caryae-semen Walsh. 
Daktylosphara caryae-semen Walsh. 

This is evidently closely related to Ph. deplanata. The galls of c.-semen are, however, much smaller, more strongly convex, projecting above, and of much finer and harder texture. They also greatly resemble smaller specimens of Ph. minima not withstanding the striking difference in the life-history of the two species, viz.: the production of a winged, migratory form in Ph. minima and the absence of such in Ph. c.-semen. 

Walsh was led from the apterous nature of the species to consider it Coccidous rather than Aphidian, and in discussing the relative generic value of winged and apterous gall-making species, remarks that "Carya possesses at least two Coccidous galls, namely, caryae-vena Fitch, which I find exclusively on the Shell-bark Hickory in August, and which is described by Fitch as Aphidian, and doubtingly referred to the genus Pemphigus, and caryae semen Walsh MS., a gall of the size and shape of a cabbage seed, which I find in prodigious numbers on the leaflets of the Pignut Hickory in July." And further on, in a foot note, he says : ' 'That these two galls are Coccidous, not Aphidian, may be inferred from the fact that the tarsi of the mother-lice are 1-jointed, not 2- jointed. And besides,Dr. Fitch himself describes the mother-lice of caryaevenae as laying eggs, and the same remark applies to those of Carym semen; whereas all true gall-making Aphidians that are known to me are viviparous so long as they live in the gall. Moreover, all gall- making Aphidians that are known to me remain in the gall till they have reached maturity and most of them acquired wings; whereas in these two galls the young larvae, almost as soon as. they have hatched out, stray away to found new galls, leaving the mother-lice behind them to lay from time to time fresh eggs." 

With our present knowledge of the Phylloxerinae we know that Walsh erred in forming this opinion. The tarsi of both species mentioned are (like those of all other known species of Phylloxera) plainly 2-jointed, he having simply overlooked the small basal joint; while the economy of the species producing winged females shows that they all originate from eggs, numerously deposited by the stem-mother on the walls of the gall. Maintaining this erroneous position regarding the Coccidous character of c. -semen, he refers it later to Shimer's genus Dactylosphaera, to include all those species which produce, or are supposed to produce, nothing but apterous individuals and proposed for all others, producing a winged generation, the name of Xerophylla. In the latter publication, after much discussion, he gives a short description of the gall and its architects on page 23, as follows: 

"Gall Carya-semen , n. sp. made by Dactylosphoera caryae-semen , new species. On the general surface of the leaflets of the Pignut Hickory (Carya glabra) in prodigious abundance, a sub- globular, smooth, seed-like, hollow, sessile gall, 0.06-0.10 inch in its widest diameter, subhemispherical above, rather flatter below, with a nipple-like opening in the middle. Walls of the gall rather stout, fleshy and not woody. The external color is greenish-yellow above and pale green below, with the open central nipple whitish. There are frequently as many as 100 of these galls on a single leaflet. Inside may often be found as many as three or four mother bark-lice, similarly shaped and of the same yellow color as those of the vitifolia gall, but on the average rather smaller and accompanied, in the same manner, by eggs or very young larvae, or both. As with the mother bark-lice of the galls vitifoliae Fitch, caryae-venae Fitch and caryae-fallax Walsh MS., the antennae of this mother bark-louse are three-jointed, joints i and 2 short and subequal, and joint 3 longer than 1 and 2 put together. The young larvae are about 0.01 inch long and of the usual shape. Almost as soon as hatched — as is also the case with the larvae of all the allied galls — these larvae stray away to found new galls. The galls themselves are very abundant about July 24th,' but by the 12th of August they were almost all empty and gaping open below." 

Dr. Shimer, referring to the same species, confounds it with his Dak. globosum, which forms a similar though much larger gall on the same leaves and produces a winged generation. Speaking of the young of the smaller galls he says "the young larva usually leaves the gall as soon as hatched and proceeds, as does the ' grape-leaf louse" (D. ? vitifoliae), to construct a new gall." 

The following notes, made in the West some years ago, will amplify the somewhat brief description of the gall by Walsh : 

Description of Gall. — Transeverse diameter 0.3-2 mm or slightly larger. Vertical diameter 0.2-0.5 mm. Hemispherical and more prominent above than beneath and frequently depressed at the centre; the depression often running out to one side. More or less projecting beneath, with a tendency to become somewhat conical, terminating in a short nipple, with a round or slightly oval orifice, surrounded by 4-10 or more rather stout and profusely pubescent recurved bracts, completely closed when young. Upper surface smooth, yellowish- green to brownish-yellow. Rather tough and leathery and slightly semi-transparent at the centre if held toward the light. 

This gall is usually extremely abundant on infected trees, often to such an extent that every leaf is completely covered. I have counted on some of the smaller leaflets over 300 of these galls, many of which, to the number of 2-5 or more, were confluent. 

This appears to be an exclusive western species and has been found at Kirkwood and elsewhere in the Mississippi Valley, upon Hicoria glabra, maturing during the latter half of July and early August. 

Phylloxera caryae-fallax Riley. 

Phylloxera caryae-fallax 

Considerable doubt has existed until lately in my mind as to the identity of the species briefly referred to under this name by Walsh in his "First Ann. Rep. of the Nox. Ins. of Ills.," p. 23, and that described by Riley under the same name in the ' 'Seventh Ann. Rep. on the Nox. and Ben. Insects of Mo.," p. 118. Walsh states that he never found a winged insect either in this gall or in those of c. -semen and c- folia, though he has opened and examined hundreds of them. My observations regarding this peculiar gall, extending as far back as 1872, run counter to those of Walsh, for I have found this particular gall swarming with the winged female. 

To account for this apparent discrepancy in independent observations, it may be stated that my own observations were made from early May until June, and that these made by Mr. Walsh were from the 17th until the end of June, or at a time when the winged form had already forsaken the galls. What, then, were the numerous larvae (?) with which he found the galls swarming, and what was their office? They could not well form new galls, as the season for that purpose was already too far advanced! 

The explanation will doubtless be found in the following facts: If the galls be opened early in May, or before the nipple has opened, they will be found filled with winged insects, pupae, numerous eggs, and what appear to be larvae. These supposed larvae, however, upon careful examination, are not larvae hatched from eggs deposited by the stem-mother, but the true sexual individuals, both males and females, produced from eggs deposited freely by the winged females. In this species therefore, the sexed individuals are (in part at least) produced within the original gall, though . winged females subsequently perform the true function of migrants and leave the galls to carry their sexed young elsewhere.

The gall of this species is one of the most common and numerous on the leaves of Hicoria (Carya) alba, and probably some other species of the genus in the states of Missouri and Illinois, extending at least as far south as Tennessee and probably throughout most of the states bordering the Mississippi. It seems to be exclusively a western species, and is at times so extremely abundant as to cover completely every leaf upon a tree, the leaves becoming much dwarfed and distorted. On some small leaflets, about 2 inches long by 3/4 inch wide, more than 300 of these galls were counted. 

The fully grown galls vary in height and diameter at base from 1-5 mm. Those more, densely crowded are narrower at base and higher in proportion. They are conical or tooth-like above and frequently lean over to one side. The under side is more or less prominently convex and more or less prolonged at the centre, with the nipple often, also, inclining to one side. The orifice is either round or oval, closely fringed with pale hairs, and tightly drawn together till maturity. The walls are rather tough and leathery. The color of the galls when younger is greenish-yellow to reddish, becoming gradually brown or black,- and brittle after the insects have left. 

Phylloxera rimosalis Pergande, n. sp. 

A very large and conspicuous gall, growing always upon the leaves of Hicoria tomentosa, bearing a great resemblance to the gall of Ph. c.-scissa, from which it differs in the round, not elongated, orifice and in some other characters. 

It is not uncommon along the Potomac near Washington and affects more generally the terminal leaves of the more succulent young shoots. It matures somewhat later than most of the other galls, the first winged females occuring the latter part of May. It grows generally singly, though occasionally 2-4 may occur on the same leaf, in which case they tend to become more or less confluent, so as to form a large, flat mass ; each retaining, however, its cell independently. It forms upon any part of the leaf, often very close to the edge, and may extend across two or even three of the transverse veins, (when the upper surface becomes somewhat uneven) but never, as far as observed, across the midrib. The horizontal diameter ranges between 3-11 mm (those growing singly being usually much the largest) and between 1.6-3.4 mm in height. The form is quite flat or but slightly convex above, with the circumference usually sharply defined and sunken below the plane of the leaf, which forms around it a somewhat elevated and quite sharp edge or rim. The disk may be raised button-like above the plane of the leaf. Sometimes the upper surface is slightly uneven or concave; or there may be a slightly convex, central elevation, with a dimpled depression on one side of it. Beneath it is much more prominent and convex, resembling somewhat that of c. -septum, except that its nipple is extremely short and conical, with the orifice round and completely closed in the younger ones, with indications that it will split when mature into 5-8 short bracts, which are closely covered at the tip and inner side with minute, white, silken hairs. The surface above is perfectly smooth, whilst the under side is sparsely beset with short, pale yellowish, radiating hairs and yellow papillae which characterize the under side of the leaves. 

It is seen to be slightly transparent, if held between the light, especially around its margin. Its walls are rather thick and hard, especially at the base. The color above and beneath is of a somewhat paler green than the surrounding surface of the leaf, occasionally faintly tinted with red at the centre and polished above. 

Each gall contains, by the middle of May, besides the single stem-mother, large numbers of eggs, larvae and young pupae, covering closely its inner walls, each with the end of the body directed toward the centre, as if they were standing on their heads. Some individuals acquire wings by about the 20th, while the majority do not reach this condition till the end of the month or the first week in June. 

Phylloxera caryae-scissa Riley
 
This gall, as already indicated, bears a close resemblance to that of hemispherica but it will be unsafe to consider them identical until further careful study is made of the latter species. 

The first galls of caryae-scissa were received in 1880 from Mr. W. H. Ashmead, of Jacksonville, Fla., found growing upon Hicoria alba. Since then the same species has been occasionally observed in the vicinity of Washington, always growing upon the leaves of Hicoria tomentosa. It is a rather rare species, and occurs for the most part singly. 

In general appearance it closely resembles that of Ph. rimosalis, for which it might readily be mistaken, but the upper surface of c.-scissa is never flattened, as in rimosalis, while the orifice is never round or nipple-like, but always a transeverse slit. All the different forms of insects, from the stem-mother to the winged female of c.-scissa, are also larger and darker, with the antennae much longer and more slender, particularly in the winged form. 

The transverse diameter of this gall ranges from 8-14 mm and and the height from 2-5 mm or more. It is about equally convex on both sides, though sometimes more prominent either above or beneath, and often with a slight, central, nipple-like projection above. The surface on both sides is more or less distinctly covered with short, fine, yellowish hairs when upon Hicoria tomentosa; while upon H. alba it is smooth above and but slightly hairy beneath. The gall is always situated between two of the transverse veins, with the slit either parallel with them or slightly oblique. When young, this slit is slightly closed and not easily seen, but forms regular, shallow lips, densely pubescent, when older. Color above and beneath pale greenish or dirty yellowish- green. 

The winged female may be found from the middle of May to the middle of June. 

Phylloxera caryae-globuli Walsh

Dactylosphaera hemisphericum Shimer

The galls of this species, as far as can be learned from the descriptions of Walsh and Shimer agree quite well with those of c.-scissa and I simply repeat here the original descriptions. That by Walsh is rather insufficient, somewhat scattered and mixed with other matter, from which it has been sifted. 

Phylloxera caryae-globuli Walsh

"Galls spherical, generally located between the veins that branch from the midrib of the leaflets of the Shag-bark Hickory, and when ripe opens below by a simple, longitudinal slit. Never exceeding one-half or one-third the extreme diameter of caryae-caulis." 

Dactylosphaera hemisphericum Shimer

Galls on the Shell-bark Hickory (C alba). 

"Gall No. 1. — This is a large subhemispherical gall, situa-ted in the parenchyma of the leaf, generally projecting above the plane of the latter. Structure somewhat thick, tough and dense, the average thickness of the walls being about .05 inch. Color pale whitish-green, much paler than the leaf, the upper surface frequently tinged with red and often quite purple-red. Size: diameter in the plain of the leaf, one-fourth to one-half inch; vertical diameter one-half."

"These galls open beneath with a slit, the length of which is about one-third of the diameter of the gall ; its direction is usu- ally in, or somewhat oblique to, that of the veins of the leaf, and when oblique, more nearly parallel with the longitudal axis of the leaf. The lips of these slits are pinched so tightly together as to project out, and their margins are either smooth or slightly hairy. Sometimes a leaf contains but a single gall, others two or more. The galls may be scattered irregularly on the leaf, or placed in one or two rows along and near the midrib, and one or two dozen may be found in a single row, placed so closely together as to be contiguous." 

"Upon opening one of these galls, I found the mother insect and her eggs, the latter in great abundance, one hundred or more studded all over the concave surface ; but very few eggs had then (June 7th) hatched. But on opening one of the largest galls, which seemed to be in a much more advanced state, I found the mother insect in the midst of a very numerous brood of newly- hatched larvae, and also many eggs still unhatched ; the new-born larvae were pale greeenish- white, while those more advanced," were of a deeper color and of all shades approaching to orange ; many were already in the pupa state, having short wing-cases. The mother insect moved in a stately manner among her numerous off- spring, apparently proud of her queenly position."

I am rather suspicious that this may be the Phylloxera caryae- globuli of Walsh; but he says that the gall of his species is " spherical " and also that the size of the insect is ".07 to .08 inch in length" and that the abdomen is blackish. But unless described from living specimens, the color is of no value, as they all turn black after death. 

Phylloxera conica Shimer. 

Dactylosphaera conicum Shimer. 
Phylloxera c.-conica Riley. 

It is rather strange that Shimer failed to mention the color of this gall, notwithstanding it is one of the handsomest of this group. There can scarcely be any doubt, however, that the gall here considered is identical with that described by him under the above name. 

The first notes upon the species were made in 1872 when it was found in Missouri on the leaves of the Bitter-nut Hickory, (Hicoria amara [Carya cordiformis]). This is one of the most widespread and common of the Hickory galls in the Mississippi Valley, and was frequently sent by correspondents for identification. The galls begin to form the latter part of May and are then almost globular, though somewhat more prominent above than beneath, with a scarcely noticeable nipple on the under side, densely covered with yellowish pubescence. Their color is a deep purplish -brown, contrasting prettily with the light green color of the young leaves ; their surface above and beneath is more or less roughened or granulated, and the appearance reminding one strongly of the galls of Cecidomya q.-pilulae of the oak. 

By the first week in June the galls are fully grown, but only contain the stem-mother, her eggs and larvae. By the middle of the month the winged female prevails, with but few pupae and still fewer larvae, while in many cases the galls have opened and migration has actively begun. The transverse diameter of the matured gall varies from 3-7 mm and their vertical diameter from 2-5 mm. Many of them are almost globular, and, as a rule, more prominent above than beneath. Occasionally, however, they are more prominent beneath. In the majority, especially the larger galls, the under side is considerably sunken beneath the surface of the leaf and much less conical and usually much paler than when younger. The color above is a dull, dark purplish brown, sometimes, how- ever, with only a brownish shade, or entirely of a dull greenish- yellow. The surface above, and sometimes slightly beneath, is densely and quite coarsely rugose and more or less distinctly pubescent, especially beneath, and covered with a more or less noticeable sticky or viscid excretion. The orifice is more densely pubescent than the rest of the gall, and splits, when mature, into 4-8 short bracts. The walls of the galls are rather stout, leathery and flexible. At full growth the inside is almost pure white, but by the time the insects are ready to leave, the color is brown all through. Generally these galls grow singly, though there are often as many as ten, of which several may be confluent, on the same leaf. 

 Phylloxera caryae-avellana Riley.

Not uncommon on the leaves of Hicoria tomentosa along the Potomac near Washington. 

Judging from the appearance of the galls, as regards size, shape and color, one might be led to conclude that we had to deal with two or more distinct species. A careful study and comparison, however, of the architects in their different stages, shows but one species. The more typical, larger and more brilliantly colored galls are the product of those stem-mothers which first settled, at a time when the development of the young leaves was most rapid and the circulation of the sap most vigorous. 

By the 20th of May many of the galls already contain pupae or even winged females, while others contain only eggs and larvae. By the middle of June most of the galls are already empty and by the end of the month have become dry and shrivelled. 

The transverse diameter varies from 5-10 mm and the height is about the same. Flat or but slightly convex above and either flush with or somewhat sunken beneath the surface of the leaf ; sub-conical or more or less globular beneath,, constricted at base and resembling somewhat in shape a diminutive filbert. The surface beneath is quite densely pubescent and with similar minute yellow papillae as those which cover the under side of the leaves, and causing a certain stickiness. The orifice, at the top of the gall, is, before maturity, closely drawn together and densely covered on the inside with white wooly hairs, opening at maturity into several short and stout bracts. Walls very thick and succulent. The color above is either greenish, yellow-green or of a more or less intense, beautiful crimson or pink ; and beneath pale greenish, or even almost white.

Phylloxera symmetrica n. sp., Pergande. 

This species, as far as its gall is concerned, appears to be closely related to, if not identical with. Ph. conifera Shimer, but as his description, both of the gall and its architect, is rather vague, brief and general in characterization, so much so as to apply equally as well to many others, it is deemed more expedient to describe it as new. 

This gall has been noticed on young trees of Hicoria (Carya) tomentosa and some other species, in the neighborhood of Washington, for quite a number of years and appears to be slowly but gradually increasing. 

Judging from the appearance of the galls alone, one is tempted to divide them into two or perhaps three distinct species, with regard to shape, size and color. A careful study, however, and comparison of the migratory forms of their architects, have conclusively convinced me that the different forms of these galls are nothing else but varieties of one species, depending, as it appears, on the earlier or later settling of the young lice, and the there- with connected more or less advanced stage of development of the young leaves. There can be no doubt that the larger and more brilliantly colored galls are the product of such of the young lice of this species which hatched in advance of the bulk of the same brood, just at the time when the development of the leaves was most rapid and the circulation of the sap most vigorous. To enable the future student, therefore, to recognize these different forms more readily, it is deemed expedient to figure each form of gall and to give each of them a variety name. All these forms are usually, at least in this locality, met with at about the same time and upon the same trees, though the two largest or more brilliantly colored galls are much scarcer than those of the typical form. As a rule, there is generally but a single gall on a leaflet, though occasionally two, or even as many as five or six, and in one instance even as many as twelve were observed upon a single leaflet, all crowded together near the base of the leaf, and more or less confluent. If there be more than one on a leaf, it will be observed that generally most of them are dwarfed, whilst but one or two have attained their full size. 

At what date the young stem-mother settles down has not been ascertained, though it must be at the time when the young leaves begin to unfold, at about the middle or latter part of April, for it was observed that by the 20th of May many contained already pupae, and a few even some winged insects, whilst others contained only eggs and larvae. By the 15th or 20th of June most of the galls are empty and by the end of the month all inmates have left and the galls become dry and shrivelled. 

Phylloxera symmetrica n. sp., Pergande. TYPICAL FORM. 

This gall forms always on the under side of the . leaf ; it is quite flat on the upper side, or slightly convex, occasionally somewhat depressed at the middle, circular, with its margin generally more or less deeply sunken below the plane of the leaf and generally concolorous with the upper side, or of a somewhat darker shade. On the under side, however, it is quite prominent and regularly conical in shape, with an opening at the tip, which, however, is tightly closed till the time arrives for the migrants to leave. At this time the apex commences to split into 4-8, more or less slender, backward-curved bracts or filaments, surrounding a more or less circular opening. The color of the lower side of the galls is either that of the leaf or somewhat paler, though rather darkest towards the apex, and their surface covered rather sparsely with the peculiar hairs and pellets of resin so characteristic of the under side of the leaves, becoming more dense towards the apex. The walls of this gall are rather stout and of a dense and firm texture, increasing in thickness toward the base. The transverse diameter above ranges between 2-5 mm and the vertical diameter from 3-4 mm. After the insects have left, the galls gradually dry up, become brown, lose their shape and disappear at last almost completely. 

In this connection it will be interesting to record here what appears to be a second crop of galls of probably the same species, though it is quite possible that later observations may prove this to be distinct. 

On the 29th of July, 1883, while examining a solitary young hickory tree near the fair-ground, in the District of Columbia, standing at a distance of between 20-50 feet from the nearest trees of its own kind, it was observed that considerable numbers of young galls had formed on the uppermost and youngest leaves, which, to all appearance, could scarcely be older than, perhaps, two or at most three weeks. A further examination of the older leaves proved that they had been infested quite profusely by galls of the species under consideration, all of which were empty and more or less dried up, though a few were still on the upper side ; no galls of any other species could be detected on any of the leaves. Notwithstanding this fact, it is still possible that these new galls were the product of some other species, the winged form of which may have migrated there from some distance. These newly formed galls were smaller and also quite different in appearance. Their upper surface is also scarcely elevated above the plane of the leaf, with the centre quite distinctly depressed. This depression is reddish or pink and is generally encircled by a pale yellowish-green ring, the under side is more prominent, though by no means conical, and somewhat paler than above. All contained, besides the females, numerous eggs and also a few larvae. The female is yellow with the eyes black, the larva pale yellow with reddish eyes; the eggs are colorless, the more mature ones faintly yellowish. 

Var. A. Phylloxera vasculosa Pergande. 

This variety is more striking in appearance and much larger than the more common or typical form. It grows also on the under side of the leaves, but is rather scarce, there being not more than from one to perhaps twelve or a few more upon a tree. Its upper surface is very much like that of the typical form, though it is often considerably sunken below the plane of the leaf and is of very much the same color. The galls proper, on the under side, are very much of the shape of a vase or urn. They are more or less constricted at base, the sides rounded and of a pear- or more or less globular form. The opening at tip, which is closed while the galls are immature, opens at maturity into bracts, similar to those of the typical form, whereby a more or less distinct neck is produced. The color of the galls is pale green, or sometimes almost white or pale yellowish, the surface being quite pubescent. Their diameter across the widest part ranges generally between 5-8 mm, and their vertical diameter between 4-10 mm. 

Var. B. Phylloxera purpurea Pergande. 

This form or variety is in shape between the typical form and var. A. It is of about the same size or somewhat larger than the first. Its base is constricted and the remaining part beyond it quite conical, with the opening completely closed. The upper side is quite flat, somewhat sunken beneath the plane of the leaf and often most beautifully red, yellowish or paler than the leaf. On the lower side the galls are either pale green or whitish and the surface covered more or less densely with pale pubescence. 

Phylloxera notabilis n. sp., Pergande. 

A few galls belonging to this species, growing along the midrib of the leaves of the Pecan, Hicoria olivaeformis [Carya illinoiensis], were received July 3, 1877, from Mr. J. Monell, St. louis, Mo., which bear a general resemblance to those of Ph. caryaecaulis when growing upon the leaves, though more convex above and more conical beneath, where they split into a number of rather long and slender pubescent bracts or filaments. The color of these galls, which had partly become quite dry, appears to have been somewhat reddish above and green or yellowish beneath. Their shape was more or less oval above and compressed laterally beneath, caused evidently by the drying of the substance. Their largest transverse diameter was 5 to 10 mm and the vertical diameter 3 to 8 mm. 

Apparently the same species of galls on leaves of Pecan was received June 1, 1891, from Mr. L. Biedeger, Idlewild, Tex., but, unfortunately, all were empty when received, the contents of most having been destroyed by some Tortricid larva. 

The same kind of galls were found during August of 1891 to be very numerous on the leaves of young trees of a variety called the "Meier Pecan," imported two years prior from Bluffton, Mo., to the Department of Agriculture at Washington, D. C. Numerous additional galls were also received from I. H. Evans, from Austin, Texas. 

The fresh galls, as found at Washington, are yellowish-green or slightly reddish, circular and bladder-like, from 2 to 10 mm in diameter at the circumference, and from 2 to 7 mm vertically; they are convex on both sides and situated either near the midrib or between the transverse veins, and generally more prominent on the upper side with a more or less distinct fovea or dimple about the middle. There is a more or less central nipple or a trans- verse slit on the under side, from which four to eight or more depressed lines radiate towards the base, along which the gall gradually splits into slender bracts in order to facilitate the escape of the inhabitants. Both sides of the galls are pubescent, though the under side is covered most densely with short, yellowish hairs. 

The great majority of these galls contained, besides the stem- mother, numerous eggs and pupae in various stages of development, numbers of the true sexes, many of which were also observed running about on the outside of the galls, and but one or a few of the winged migrants. This leaves no doubt that most of the sexes were the progeny of the pupae, whereas the few migrants were destined to perpetuate their species on distant trees. 

Phylloxera globosum Shimer. 

Dactylosphaera globosum Shimer. 
Dactylosphaera coniferum Shimer. 
Phylloxera c.-globosum 

I have had no opportunity to add anything new to what has been recorded by Shimer, and reproduce such parts of the original description as undoubtedly have reference to this species, substituting migratory female for his term male. 

In his original description Shimer has confounded this large gall and its architects with those of the rather minute galls of c.-semen Walsh, found growing at the time upon the same leaves, notwithstanding that, as he himself states, none of the small galls contained the winged form, but were simply crowded with the so-called larvae which, as has already been shown, were, without much doubt, the true sexes. 

"Gall variable in size, often numerous in the parenchyma of the leaf, others on the veins and leaf stalks, all opening on the lower side of the leaf, with a very small orifice; smoothish, of a somewhat leathery structure, pale yellowish-green, glaucus or dark green; sub-globose or some- times somewhat irregular, without any of the mealy sugary dust within, which is common in galls of the Aphis family. Dactylosphaera coniferum Shimer, I consider to be but a variety of D: globosum.

Phylloxera caryae-gummosa Riley. 

Forming pedunculate, ovoid or globular galls on the under side of leaves of Hicoria alba [Carya tomentosa]; the gall white or yellowish, pubescent, and gummy or sticky; opening below in a fibrous point. The eggs are almost spherical, pale and translucent. Larvae, motherlouse and pupa quite pale, the red eyes and eyelets strongly contrasting. The winged insects with difficulty distinguished from some of the other species, a difficulty made all the greater from the fact that other species get caught in the sticky surface of the gall. 

Phylloxera caryaevenae Fitch. 

Pemphigus ? caryaevenae Fitch. 
Phylloxera caryaevenae Riley.

The galls of this species we readily separated from those of any of the other species found upon Hicoria. They resemble more closely those of certain of the Cecidomyids occurring on different species of oaks and other plants. 

They always form, either along the main rib or more frequently along the transverse veins, shorter or longer folds or plaits projecting more or less evenly from both sides, though usually more prominent above, where they form elongate ridges or carinae, which are often transversed by 3-5,, or more, short, elevated branches, about equal in length to the diameter of the gall. The opening or slit is always on the underside and, while fresh, is tightly closed except at the outer end, and covered by a delicate white or greenish pubescence which also more or less completely covers the entire surface beneath. The color is generally yellowish-green, though very frequently also brownish or purplish. Two or more are often confluent, so that their length varies from 6-14 mm or more, and their diameter from 2-3 mm. 

The gall begins to form early in May. It occurs not only upon Hicoria tomentosa but upon several other species of Hicoria and is widely distributed over the eastern half of the United States, having been observed from New York to Florida, and west as far as Illinois and Missouri. 

No winged migratory female has yet been observed, but the most remarkable fact is that I have been unable to discover in any of the many galls examined from 1880 to 1890 a sexual form, though examinations were made during different months. The only occupants thus far found in these galls were the true stem- mothers (of which 1-3 have been observed in the same gall) , their eggs and the wingless sexuparae in different stages of development. 

By the middle of August, when the majority of the galls had become dry and empty, but a few remained still green and contained the still living, though much shrunken, stem-mother, a small number of eggs and a few larvae, but no migrants or sexual individuals. 

On July 19, 1890, when many of the galls still contained their usual inhabitants, extended and careful search was made to discover the whereabouts of the larvae after leaving the galls. Small colonies, absolutely identical with those found within the galls, were finally discovered snugly hid away either in deep cracks of the bark or at the bottom of deep and more or less completely closed depressions, which are found on the trunk and stouter twigs and which are caused by the decay and dropping out of small branchlets. Here the insects live upon the juices from the tender bark which forms at the bottom of the cavities. These colonies usually consist of the stem-mother, a number of fully grown apterous females and larvae (both the direct progeny of the stem-mother) and eggs of three different sizes. The smallest, and most numerous of these eggs, correspond exactly in size and general appearance with those deposited by the stem- mother in the galls, while the others are about twice as large but yet of two sizes, the larger ones of a regularly ovoid shape, the smaller more conoidal in outline. The former produce, after a few days, the true sexual female, and the latter the male, which pair, when the female brings forth her single impregnated or winter egg which doubtless hibernates within the cavity. 

In some of the depressions no stem-mother is found, but only the other forms here described and a few of the winter eggs. 

During the summer of 1902 another effort was made by me to discover, if possible, the winged migrant of this species, though without avail. Unfortunately nearly all the trees on which the galls used to be plentiful had been cut down, leaving but a few small shrubs in that particular locality, with still fewer galls on some of the leaves. These galls were also extremely scarce on trees in the woods some distance to the north, in all of which the usual apterous forms and some eggs were present, though not a single one of the winged migrants. That this form, after a shorter or longer interval must exist, seems quite plain, while otherwise the species is doomed to become extinct, since the migration of some of the apterous forms from tree to tree, especially if such trees should grow at some distance from each other, must naturally be rather slow and uncertain. I take it, therefore, for granted that the spread of this species depends, as in other species, on a winged migrant, which sooner or later will be found. 

Phylloxera caryaecaulis Fitch. 

Pemphigus caryacaulis Fitch. 
Dactylosphcera caryae-magnum Shimer. 
Dactylosphcera spinosum Shimer. 

Up to the present time these three forms of galls have been considered as quite distinct species on account of their dissimilarity, two of them being smooth and the other more or less profusely covered with fleshy spines. But a careful study of the architects of these forms forces the conclusion that they are identical, there being no tangible characters by which to separate them. The spiny form of gall always grows upon trees with pubescent leaves, such as Hicoria tomentosa, while the smooth forms are always found upon trees with smooth leaves, such as Hicoria glabra, amara and probably other species. 

Ph. c.-magna Shimer may also be considered as a variety of caryaecaulis. The form is found in Missouri growing on the petioles and bases of the leaflets of Hicoria amara. Some of the specimens also closely resemble those of subelliptica Shimer, which probably belongs to it, but of which I have not yet succeeded in obtaining the migratory form. On account of some slight differences in the gall, which are no doubt due to the specific differences of the infested trees, c.-magna may perhaps be allowed to remain under a variety name, though the architects in their different stages, as far as examined, show no differences by which to separate them from the typical caryaecaulis. The galls of this variety vary from 4-20 mm in size, the normal being about 10 mm. They occur on the under side of the petiole and the base and often the midrib of the leaves, and, when in the latter position, they generally project somewhat on the upper side. The shape varies from globular to sub-conical, or broadly ovoid. The surface is quite densely covered with a minute pubescence which gives it a slightly velvety appearance. The orifice beneath is rather small and transverse and tightly drawn together before maturity. Color greenish-white to yellowish-green beneath and beautifully crimson on the upper side. Usually single, though occasionally two or more may become confluent, with their cells, however, well separated. 

Phylloxera caryaecaulis Fitch. 

Pemphigus caryacaulis Fitch. 
Dactylosphcera caryae-magnum Shimer. 
Dactylosphcera spinosum Shimer. 

Up to the present time these three forms of galls have been considered as quite distinct species on account of their dissimilarity, two of them being smooth and the other more or less profusely covered with fleshy spines. But a careful study of the architects of these forms forces the conclusion that they are identical, there being no tangible characters by which to separate them. The spiny form of gall always grows upon trees with pubescent leaves, such as Hicoria tomentosa, while the smooth forms are always found upon trees with smooth leaves, such as Hicoria glabra, amara and probably other species. 

Ph. spinosa Shimer is evidently but a variety and more numerous than the typical form in localities where the pubescent-leaved species of Hickory prevail. It is often considerably larger than the typical form and is always more or less covered with short, fleshy spines. It closely resembles, also, c.-spinuloida, which, however, is still more densely covered with longer and more slender spines. The more striking differences are, however, noticeable in the migratory females, which in caryaecaulis have shorter and broader wings, different antennal characters, comparatively longer legs and the two oval orange or blackish spots at the end of the body. 

Phylloxera caryaecaulis Fitch. 

Pemphigus caryacaulis Fitch. 
Dactylosphaera caryae-magnum Shimer. 
Dactylosphaera spinosum Shimer. 

Up to the present time these three forms of galls have been considered as quite distinct species on account of their dissimilarity, two of them being smooth and the other more or less profusely covered with fleshy spines. But a careful study of the architects of these forms forces the conclusion that they are identical, there being no tangible characters by which to separate them. The spiny form of gall always grows upon trees with pubescent leaves, such as Hicoria tomentosa, while the smooth forms are always found upon trees with smooth leaves, such as Hicoria glabra, amara and probably other species. 

The typical form, growing upon the young and succulent limbs, petioles or the midrib of the leaflets of Hicoria glabra, occurs over the eastern half of the United States. 

The size of the galls varies from 5-25 mm in diameter. Those growing singly often attain immense proportions, but when numerous or crowded they are reduced in size and often confluent, so as to form an elongated mass. Before maturity of the inhabitants the gall is closed, but as soon as any of the inmates have acquired wings, it cracks transversely into 3-6 or more broad and more or less irregular bracts so as to allow the mature migrants to escape, and to leave room and food for the younger individuals. The color is pale yellowish-green, more or less tinted with red or crimson. The walls of the galls are rather thick and succulent when young, becoming more tough and leathery when older and hard, brown or black when empty and dry. 

 Phylloxera spinuloida Pergande, n. sp. 

The galls of this species, as already remarked, are very similar and closely related to those of spinosa, for which, without comparison of the migratory females, they might easily be mistaken. They are, as a rule, more regularly globular, or but slightly conical, covered with numerous irregular, more or less radiating, low ridges, which are rather plentifully provided with irregular, long, fuzzy, fleshy spines or filaments. They grow generally upon the petiole of the leaves, which they often almost completely encircle, causing, at 'the point of junction with the petiole, a curve or bend. They also occur on the midrib of the leaves. When mature each gall bursts at the apex in a more or less irregular opening. The diameter of those examined varied from 5-15 mm. The color appears to be quite uniformly greenish-yellow, or brownish-yellow on one side. 

Phylloxera devastatrix Pergande, n. sp

The galls of this species resemble very closely the smaller galls of caryaecaulis and also those of perniciosa. From both of these, however, the species differs markedly in the antennae of the winged form, which are much more slender than in either of the other two, with scarcely a constriction above the lower sensorium and with the anterior sensorium much shorter. 

Its principal points of attack, as in the other species of this group, are the tender twigs, petioles and the midrib of the young leaves; but the leaf-buds and flower-buds are also often involved so as to prevent the setting of the fruit. 

It appears to be an exclusively western or southwestern species, infesting the Pecan-hickory (Hicoria olivaeformis [Carya illinoiensis]) during May and early June. This gall was first received in 1887 from Mr. M. E. Winster of Staunton, Adams County, Miss., and again in 1889 from Mr. H. M. Johnson of Marston, LA., with the statement that it was greatly damaging the trees. It is either globular or more or less irregular in shape, especially where much crowded. Before opening it is often provided with a short more or less distinct nipple, most prominent in the younger galls, and becoming almost obsolete in the more mature form, when its position is indicated by a more or less densely pubescent spot. It splits transversely into four or more broad bracts, similar to those of caryaecaulis. The size varies from 3-15 mm. Surface smooth, green or yellowish-green, and often beautifully red on one side while young, turning brown or black and soon drying up after the architects have left. 

Phylloxera Georgiana Pergande, n. sp. 

The galls of this species closely resemble those of Ph. devastatrix, being of the same shape, size and color; but the winged form is quite different and may readily be distinguished by its much paler wings and venation and particularly by the shorter antennae and much larger sensorial membranes of the third joint. 

The galls grow either singly or in close clusters upon the tender twigs and petioles and often recall in appearance the galls of Cynips q.-ficus. Those growing in clusters are more or less irregular in shape, whereas those growing singly are quite globular and frequently provided with a short nipple. Their size varies from three-sixteenths to one-half inch in diameter; color either uniformly greenish-yellow, sometimes reddish on one side or around the base, or entirely dark red. 

Phylloxera subelliptica Shimer. 

Dactylosphcera subellipticum Shimer. 

Of this species I am familiar with the gall only and reproduce, therefore, Shimer' s description as published in the Transactions of the American Entomological Society of Philadelphia, Vol. 2, 1868, page 389: 

"On June 7th I observed, placed in the common petiole of the leaf, larvae, elongate, subelipsoidal, nut-like galls, of a deep leaf-green color, mottled with paler green, and somewhat nodulated ; some were irregular, being on the side of the stem ; but most of them are quite regular in form and completely surrounding the stem ; in these latter the leaves are very much dwarfed. The opening is on the middle of the side, slightly elongate, but at this date so close as to be scarcely apparent. These galls contain capacious cavities, in which were found vast colonies of larvae, and an abundance of eggs. Transverse diameter five-eighths inch ; conjugate diameter three-eighths inch. " By June 20th these galls had considerably changed in appearance, being contorted into different shapes ; they had began to crack open, having transverse fissures on their outer surface. The first one opened contained many hundred winged unagos, all dead, and in the midst of them was a large syrphidian larva. I found only one gall that contained perfect living imagos, the inhabitants of all the other galls that were exam- ined haying been destroyed by various enemies."

This may possibly be but a variety of Pk. caryaecaulis Fitch, but not having had an opportunity to study its architects I prefer, for the present, to leave it as a distinct species. 

Phylloxera perniciosa Pergande, n. sp. 

[Key]
Galls more or less globular or irregular, terminating in a tooth-like nipple.
Growing on tender twigs, petioles, or ribs of leaves, often confluent. Smooth. Diameter 2-8 mm.

This is one of our most destructive species, occurring in the District of Columbia, Maryland, Virginia and Pennsylvania, where it takes the place of Ph. carycecaulis and Ph. magna, having the same habit and there proving as disastrous to the foliage of Hicoria tomentosa as those prove in the North and Northwest to the other species of Hicoria. It attacks, as do those species, the tender twigs and petioles and the different parts of the leaves at times in such immense numbers as to completely deform and cause them to dry up and drop to the ground, literally, at times, defoliating the tree. My attention was first called to this particular species in May, 1883, when, passing through a strip of woods bordering the Potomac River in Virginia, I observed that the air was swarming with the migratory form. The insects were settling not only on the leaves of the different species of Hicoria, but on all other kinds of trees and shrubs and even on weeds, on all of which they were actively engaged in depositing their eggs; but they all originated from a tall slender tree of Hicoria tomentosa, every leaf, petiole and young twig of which was affected by the galls. 

[Pergande provides a detailed timeline of oviposition and development]

By the 28th of April most of the young stem-mothers had settled either on the young petiole or mid-rib, on the cross-rib, or on the more fleshy parts of the young leaves, where small depressions or cavities had been formed. 

By May 8th it was noticed that the galls had been formed on almost all parts of the leaves or on the petioles or on the more tender twigs. The more perfect specimens were growing singly, resembling a blunt tooth or thorn, those on the leaves projecting about evenly on both sides though ordinarily more prominently on the under side. The stem-mother had already by this time acquired full growth and began depositing numerous eggs, covering almost the whole inner surface of the gall, the eggs placed on end and side by side reminding one in miniature of the regular crystallizations in the cavities of some geode. By the 18th of May the galls contained, besides the eggs, both larvae and pupae in different stages of development. By the 25th the winged insects had formed and were leaving the galls in large numbers and settling, as at the same time the previous year, on all kinds of vegetation in the neighborhood of the tree on which they had developed. 

To sum up the life-history of this species, the winter or impregnated eggs are deposited early in June in all sorts of sheltered positions, especially on the upper portions of the tree; they hatch early in April of the following year, remaining dormant some ten months. The stem-mother attains maturity and begins ovipositing in about twenty days after hatching, while the winged migratory females (sexuparae) mature and begin to leave their galls in about twenty days after the first eggs are laid. The first sexual individuals appear about ten days subsequently and some ten days further elapse before the true female, after pairing, begins to consign her single egg to its winter quarters. 

Phylloxera Caryae-ren Riley. 

Since the description of this gall nothing new has been added regarding its earlier stages and development ; nor have I had the opportunity of studying its architects. 

The galls usually grow, like those of the preceding species, in clusters, though occasionally singly, upon the main petiole, the leaf -stems or the midrib of the leaves of Hicoria glabra, usually along the underside. Frequently, however, they are so closely crowded together as to completely encircle the petioles, never becoming confluent, however. They are always placed transversely with the axis of the petiole, more or less distinctly reniform and divided along their entire transverse length in two equal halves or lids, the edges of which are incurved and pressed closely together while young, but spread open for some distance when mature to allow the insects to escape. The size varies from 2-15 mm and the outer surface is densely pubescent and of a pale green color, with the interior smooth and yellowish-brown. The walls are rather thick and hard and similar in composition to the husks of the nuts. 

North American Phylloxerinae affecting hicoria (Carya) and other trees