Callirhytis tubicola (agamic)

Amphibolips confluenta (agamic)

Amphibolips quercusinanis (sexgen)

Amphibolips quercuscoelebs (sexgen)

Melikaiella ostensackeni (sexgen)

Dryocosmus quercuspalustris (sexgen)

Amphibolips quercusspongifica (sexgen)

Neuroterus quercusirregularis (sexgen)

Neuroterus quercusverrucarum (agamic)

Andricus chinquapin (sexgen)

Callirhytis clavula

Callirhytis nigrae (sexgen)

Cynips quercus tubicola n. sp.

Host: Quercus obtusiloba [stellata]

Clusters of yellow, tubular galls with red spines, on the underside of the leaves. The gall is a perpendicular tube 0.3 to 0.4 [no unit given] long, slightly narrowed at its point of attachment, open at the other end, yellowish and covered on its outer surface with numerous red spines. If cut open longitudinally, its inside appears divided into three compartments like so many floors, by two horizontal partitions; the compartment nearest to the base is empty, the intermediate one contains the insect and the third one is open at the top. 

If the red spines are removed with a knife and the surface of the gall examined under a strong lens, it shows dense longitudinal fibres and numerous little pale yellow crystals. The substance of the gall itself is hard, as if crystalline. From 30 to 40 of these galls are found sometimes on the underside of a single leaf. I frequently found them near Washington, in October and obtained the fly soon afterwards, each tube containing a single fly.

Cynips confluens

Quercus rubra. Red Oak. Large, smooth, globular gall on the leaves, filled, when ripe, with a brown, spongy mass. Diameter about 1.5.

These galls are more than one inch, sometimes almost two inches in diameter. "They are green and somewhat pulpy at first," says Dr. Harris, "but when ripe, they consist of a thin and brittle shell, of a dirty drab color, enclosing a quantity of brown, spongy matter in the middle of which is a woody kernel about as big as a pea. A single grub lives in the kernel, becomes a chrysalis in the autumn, when the oak-apple falls from the tree, changes to a fly in the spring and makes its escape out of a small round hole which it gnaws through the kernel and shell. This is probably the usual course, but I have known the fly to come out in October." 

I am more inclined to agree with Dr Fitch who supposes that there are annually two generations of this fly. They are not rare around Washington, but I have never found them so abundantly as they seem to occur in other localities. On the first of June I found balls of this kind already ripened, measuring one inch and a half in diameter, of the usual drab color and somewhat greenish only at its base. One of them, which I opened contained a larva. On the 13th of June another gall was opened, it contained the perfect insect, but with wings yet wet and folded and evidently not quite ready to escape. 

On examining the specimens of this gall in my collection, I notice two varieties of it. The one, the surface of which is glossy, occurs on the smooth leaves of the red oak; the other, with a more opaque, almost downy surface, always occurred on tomentose leaves. I am unable to tell at present from what kind of oak the latter leaves were taken and hence, whether the gall is a different one or only a variety. I know that the same gall is said to occur on the black oak [Quercus velutina]; I found a similar one on the blackjack oak (Q nigra) and by cutting it open, obtained a gall-fly closely resembling C confluens.

[OS also describes Cynips aciculatus, reared from galls "answering exactly" Harris' description of C confluens but a distinct species based on adult morphology. C aciculatus was later synonymized with A confluenta.]

Cynips quercus inanis (Syn C confluens Fitch, non Harris)

Quercus rubra. Red oak. Large, smooth, globular brownish-yellow gall, attached to the underside of the leaves, inside with whitish, delicate filaments radiating from the kernel to the shell. Diam about an inch.

Very like gall No. 1 [Cynips confluens, now Amphibolips confluenta] at first glance, but smaller, the specimens in my possession measuring an inch or a little more in diameter. It is also fastened to the leaf by a small point on its surface. The outside of this gall shows no other difference from the oak-apple of the red oak but the size. The inside on the contrary distinguishes them at once; instead of the spongy, brown mass with which the other gall is filled, this one is almost empty, the kernel being kept in its central position by a certain number of whitish filaments which radiate from it to the shell. 

Habitat: DC

Cynips quercus coelebs n. sp.

Quercus rubra. Red Oak. Elongated, fusiform, pale green gall, with a pedicel, inserted on the edge of the leaf and being the prolongation of a leaf-vein. Length about an inch. 

The pedicel is about 0.15-0.2 long; the gall itself is an elongated, subcylindrical body, tapering on both sides, 0.6 or 0.7 long; its apex is slender, about 0.1 or 0.15 long. I have found three specimens of this gall near Washington, in June; two are inserted on the margin of the leaf, not far from the stalk; the third is on the leaf-stalk itself, but so that on the side of the gall the leaf originates about half an inch above its place of insertion, whereas on the other side the beginning of the leaf corresponds exactly to the place of insertion of the gall-stalk. In all the three cases, the gall is the prolongation of a vein; in the latter case, the vein, in consequence of the growth of the leaf, has become entirely independent of the blade and appears to be growing out of the leaf-stalk. 

The inside of these galls is hollow; each contains a brownish, oblong nucleus, kept in position by woody fibers. On the 17th of June I obtained the gall-fly from one of my specimens; on June 28th a parasite from the other; the third was dry when I found it. The gall-fly is a male.

Cynips quercus modesta n. sp.

Quercus rubra. Red Oak. Small, irregular, hard protuberance, projecting on both sides of the leaf and not differing from it in color. Diameter about 0.15. 

The two specimens in my possession are a little longer than broad, rising abruptly on the upper side of the leaf, more subconical on the opposite side. The substance is hard, almost woody. I cut one of my specimens open and found that notwithstanding its small size, it contained five hollows, each producing the comparatively large fly. Three of the flies had already escaped from this gall, the two others, although perfectly formed, were still in their cells; a third specimen I reared from the other gall (end of June). On the whole, this gall has so little peculiar and characteristic about it, that I apprehend it will be somewhat difficult to identify it, unless by the fly. 

Cynips quercus palustris n. sp.

Quercus palustris. Pin oak. 

Globular, hollow galls on the buds and young leaves. Diameter 0.35-0.4.

Shell green, succulent, hollow on the inside, containing a whitish, globular body, about 0.1 in diameter, which rolls freely about, not being fastened to the shell.

I found these galls quite commonly very early in the spring, on the buds of the oak, before any leaves had appeared. At that early season already, the globular, whitish body contained the pupa. When the leaves came out, I observed the same gall on them, generally close by the leaf-stalk. The fly was obtained from the galls brought home on the 17th of May. In the woods, most of the galls were found empty on the 25th of May. Still, some of them contained the fly yet. 

Several galls of this kind were observed on the pin oak; they seem to occur also on other oaks, but I neglected to observe on which, chiefly on account of their appearing before the leaves were developed. The gall shrinks completely when dried but can be preserved in spirits. 


Cynips confluens

On examining the specimens of this gall in my collection, I notice two varieties of it. The one, the surface of which is glossy, [C confluens] occurs on the smooth leaves of the red oak; the other [Cynips spongifica], with a more opaque, almost downy surface, always occurred on tomentose leaves. I am unable to tell at present from what kind of oak the latter leaves were taken and hence, whether the gall is a different one or only a variety. I know that the same gall is said to occur on the black oak [Quercus velutina]; I found a similar one on the blackjack oak (Q nigra) and by cutting it open, obtained a gall-fly closely resembling C confluens.

Cynips quercus irregularis n. sp.

QUERCUS OBTUSILOBA [stellata]. Post Oak. Irregular, flattened galls, projecting on both sides of the leaf, yellow, when ripe and dry, and of a substance not unlike soft wood or pith, enclosing several hollow kernels. 

Cynips quercus irregularis n. sp. 
The sizie of this gall depends on the number of kernels it contains. 
One specimen in my possession, about 0.4 long and 0.28 broad, is pierced with 16 holes through which its inmates had escaped; but they may have been small parasites. The average size of these galls is between a quarter of an inch and half an inch in length. Sometimes several of them are packed closely together and separated only by furrows. The color of the galls, when ripe is a light leather-yellow; their substance resembles then the pith of a plant, being softer than wood and still hard enough not to shrink in drying. When examined under a lens of moderate power, the gall appears to be covered with numerous little points or small cones, each bearing a few short hairs on the tip, which under such a magnifying power gives the surface a shaggy appearance. On the 29th of May, when I first discovered these galls, some of them, although yet green, were already pierced with holes. Other galls still contained larvae much later in the season. The only fly obtained from these galls was accidently injured, so that I can give only an incomplete description. 

Cynips quercus verrucarum n. sp.  

Quercus obtusiloba [stellata]. Post Oak. 

Small, round, pubescent, wart-like excrescences on the underside of the leaves. Diameter about 0.08. 

They occur in numbers on one leaf in the latter part of the summer ; when the leaf is dead, the wooly pubescence of these excrescences is pale ferruginous, but earlier in the season, it is I suppose, snow-white, as are similar excrescences on other oaks. 

Cynips quercus fusiformis, n. sp.

Quercus alba. White oak. Elongated, fusiform gall on a pedicel. mostly on the margin, sometimes on the surface of the leaf. 

Resembles the preceding [[quercuscoelebs](https://www.gallformers.org/gall/593)], but is much smaller. The pedicel is 0.2 or 0.8 long, the fusiform body about 0.15 or 0.2 and ends in a point. The pedicel is a prolongation of one of the leaf-veins. The color of the gall is that of the leaf, that is, it is green as long as the leaf is green and fades with it. This gall was first communicated to me by Mr. T. Grlover, at the Maryland Agricultural College. He had obtained a parasitical Hymenopteron from it. In May 1861 I found several specimens of the same gall on a young white oak and succeeded in rearing the gall-fly. 

Cynips quercus arbos Fitch

Quercus alba

"Swellings similar to those of Cynips quercus tuber, growing on the tips of the limbs of aged and large white oak trees." - Fitch

Is it identical with the following gall? But according to Dr. Fitch, this gall differs from that of C. quercus tuber by occuring on old and large trees only, whereas my gall No. 25 is found on trees of different age and size. 

[Unnamed] 

Quercus alba

Club-shaped, woody swelling at the tip of the limbs.

In June these swellings are yet green; later in the season, they become brown, hard and woody; in autumn, the leaves emerging from their tip, break off and the swellings at the tip of the limbs are easily noticed. 

They can be recognized immediately by their club-shaped form, the vestiges of the leaves (usually three), broken off from their tip and the flattened, uneven surface between these vestiges, with the round hole, through which the insect escaped, generally in the centre. If cut lengthways in two, an elongated cavity is found just below this hole, and under this, a second, smaller, more rounded cavity. The latter contains the larva. 

Sometimes there are two cavities of the latter kind and consequently two larvae occur in the same gall. On the 4th of July I found a pupa in an advanced state of ripeness in one of these galls; in the adjoining cell however was still a larva. I did not succeed in obtaining the gall-fly; instead of it, one of the specimens gave me Hydnocera verticalis Say, a col- eopteron, living, as it seems, parasitically on oak-galls, as I obtained it also from the oak-bullet gall (C. quercus tuber) of Dr. Fitch. 

This gall is very common around Washington. Is it the gall of Gynips quercus arbos Fitch (Reports, Vol. II, No. 310)? From the gall of C. quercus tuber Fitch it is easily distinguished by its more constant form, its more uniformly woody consistency and the absence of the seed-like shells, containing the larva. I have found similar swellings on other kinds of oaks also. 

Cynips quercus tuber Fitch

Quercus alba

Swelling of the small limbs or twigs

These galls are easily distinguished from the club-shaped galls by their inside. "On cutting into these galls, says Dr. Fitch, the small limb on which they grow is found to have its wood thickened or swollen, and over it, forming the chief bulk of the tumor, is a corky substance of a yellowish-brown or snuff" color, between which and the wood are several small hard grains, resembling seeds, each having a cavity in its centre," etc. 

The flies which I obtained from these galls agree with Dr. Fitch's description, except that the neuration of their wings shows that they do not belong to the true gall-flies (Psenides) of Hartig. The second segment of the abdomen is shorter than the third, the radial area is closed by the prolongation of the subcostal vein along the anterior margin and the areolet corresponds more to the middle than to the base of the radial area, all characters distinguishing them from the true gall-flies. Still, I am at a loss to say to what genus they belong. I thought for some time that they agreed with Amblynotus Hartig, as defined in Reinhardt's recent Monograph of the Figitidse (Berl. Entom. Zeitschr. 1860), but the antennae of the male, which I examined repeatedly on the living and the dead insect, appeared to me 15- and not 14-jointed. The male of Dr. Fitch's C. quercus tuber has 14-jointed antennae. My 9 , like Dr. Fitch's, have 12-jointed antennae, if the last, very elongated joint, is counted for one. The female of Amblynotus, according to Reinhardt, has 13 joints. 

Cynips quercus nigrae n. sp.

Quercus nigra [marilandica] 

Irregular, elongated swelling on the under side of the midrib of the leaf.

Found two specimens, in June. One of them extends for about an inch along the vein, the other is shorter; both are greenish, and about 0.2 or 0.3 broad. Each gall contained several flies, which escaped between the 20th and 22nd of June, after which the larger gall appeared pierced with nine holes. 

On the Cynipidae of the North American Oaks and their Galls