Callirhytis glandulus (agamic)

Callirhytis perditor (agamic)

Amphibolips quercusjuglans (agamic)

Amphibolips gainesi (agamic)

Amphibolips quercusfuliginosa (agamic)

Melikaiella fructicola (agamic)

Callirhytis quercusoperator (agamic)

Callirhytis eldoradensis (sexgen)

Andricus glandulus sp. nov

Cynips quercus glandulus

Cynip glandulosus

Gall.--In the cups of acorns of swamp white oak (Quercus platanoides [bicolor]), burr oak (Q macrocarpa), dwarf chestnut oak (Q prinoides), chestnut oak (Q prinus [montana]) and probably other trees belonging to the white oak group. Monothalamous. The gall is formed in a cavity, causing more or less bulging and swelling of the acorn cup. It is an elongate body averaging when well developed 5 mm. long and not quite half as wide. The sides are sometimes parallel, but more often slightly bulging or sometimes longitudinally ribbed or smooth; whitish green, yellowish, often with a roseate tinge. The base is truncate and covered with a whitish down. The crown is flattened or slightly concave with a small central conical nipple. The mouth of the cavity in the acorn cup is either strongly fimbricated or simple, according to the nature of the cup scales, and thus either concealing the gall or exposing a large part of it. The larva lies in a cell near the top of the gall. Sometimes the galls deform the acorns. 

Habitat: N. Y., Penn., N. J., IL., Ohio, Mo., Conn. 

Many years ago the late C. V. Riley gave me a specimen of a gall-fly which he said he had raised from the oak-pip gall in the acorn cups. But the species was never described by him, except from the gall which he termed Cynip quercus glandulus. While collecting in the pine barrens at Lakehurst, N. J., very early in May, I took a number of female gall-flies on the twigs of the dwarf chestnut oak, presumably ovipositing in young acorns. My specimens agree in all particulars with the one given to me by him, and are described above together with his as being the producers of the oak-pip galls. The ripe and well developed gall falls out of its cavity to the ground, where the larva remains within it either to the following spring or the next year. Described from twelve females, three of which have the anterior parallel and lateral grooves black and narrowly edged on each side by the same color. 

Andricus perditor

The gall of this species is practically nothing more than a deformed acorn of the scrub oak. The eggs are deposited early in spring in the very young acorns of the first year's growth. They are reddish and mature in September and October. When fully developed they turn brown like the color of the acorns. 

Amphibolips prunus

Cynips quercus prunus

This is the well known oak plum gall which grows on the acorn cups of red oak (Q. rubra), black oak (Q. velutina), scarlet oak (Q. coccinea), and scrub oak (Q. nana [ilicifolia]). It is bright red, more or less globular and often looking like a marble. When fresh it is solid but fleshy and of a pink color inside, shading into yellow toward the middle, where there is a single large larval chamber. When mature it becomes blood red and when old and dry it becomes shriveled and quite hard. It matures late in August or early September, and the fly emerges the following spring. 

Amphibolips gainesi

The gall is attached by a single small point to the side of an acorn cup of the black jack oak (Q. marylandica) . It is perfectly round and smooth and measures from 24 to 42 mm. in diameter. When dry it is brown and rusty brown inside and of a dense corky consistency. Internally it contains a large central larval chamber, which is firmly imbedded in and adherent to the surrounding mass. The imago is one of the largest species and is closely allied to A. prunus. The gall is probably red or yellow when fresh. 

Habitat: Texas. 

Amphibolips fuliginosa

A small red gall measuring from 8 to 12 mm. in diameter. It is rounded or spherical, smooth, and of a corky texture, with a central larval cell. Dr. W. H. Ashmead states that the galls drop from large trees of willow oaks (Q. laurifolia) in August and that he was unable to find out whether they grow on the twigs or leaves. I am of the opinion that it is an acorn gall, growing on the cup, owing to the resemblance of the adult and structure of the gall to that of A. prunus. 

Habitat: Florida. 

Callirhytis fruiticola

The gall of this interesting species occurs in the meaty part of acorns of scarlet, red and black (Q. tinctoria [velutina]) oak and probably others belonging to the red oak group. It consists simply of a hard rounded kernel or larval cell imbedded in the inside of the acorn. Sometimes there are more than a dozen larval cells closely pressing upon one another and filling the whole interior of the acorn. The gall matures in the autumn and the adult emerges next spring. A gall similar to that of fruiticola was found by Mr. L. H. Weld, at Evanston, IL., in the acorn of the swamp oak {Q. platanoides [bicolor]) which, when the adult is known, will undoubtedly prove to be a new species. 

Habitat: N. Y., Conn., N. J., Penn., IL., Mich., Mo. 

Andricus operatola

Forms a flattened tooth-like or wedge shaped gall on the outside between the cup and the acorn with the ends more or less protruding. It lies in a depression and is of a light brown color. Often there are as many as eight galls on a single acorn. It occurs on red, scarlet, black and scrub oak. According to H. F. Bassett the galls mature in autumn, and early in the spring following part becomes imagos, another part remaining in the larval state another year, while a few remain in this condition still longer, and, as suggested by C. V. Riley, may develop the third year. 

Habitat: Ottawa, Can., Conn., N. Y., N. J., Penn., and westward. 

Andricus eldoradensis sp. nov.

Gall. — Inside the acorns of Q. agrifolia. Rounded bodies or larval cells, sometimes filling the whole interior of the acorn. In shape and structure they are like those of Callirhytis fruiticola. 

Habitat: Alameda and Los Angeles Co., Cal. (A. Koebele). 

The flies of this species are from Los Angeles Co, and are labeled "from acorns of Q. agrifolia", while the galls are from Alameda Co. It is barely possible that the flies have nothing to do with the galls, but both bear the same number, 109. 

The North American acorn galls with descriptions of new species