Andricus quercusutriculus (Bassett).

Connecticut to Florida, west to Illinois.

Ecology: Produce leaf galls on Quercus alba, Quercus chapmanii, Quercus stellata.

Cynips quercusutricula Bassett, 1881. Canadian Entomologist. 13: 78, female, gall.
Andricus (Andricus) utriculus Ashmead, 1885. American Entomological Society, Transactions. 12: 295.
Andricus pruinosus Bassett, 1900. American Entomological Society, Transactions. 26: 311, female, gall.

Andricus utriculus

Quercus alba, breviloba, chapmani, margaretta, stellata
Leaf galls, integral
Globular, thin-walled, green, 3-4 mm in dia, projecting on both sides of leaf, usually single, in May-June.

[Photo caption]
On Q alba. Also on breviloba, chapmani, stellata, margaretta. Adults emerged Apr 25 (DC); June 16 (IL).

Andricus utriculus

White oak

Leaf galls
globular, green or purplish, 1/6 in.

Cynips quercus utricula, n. sp.

Globular, monothalamous galls on the petioles and leaves of Quercus alba. Thin-walled, .15 of an inch in diameter, green or purplish, pubescent. Sometimes entirely preventing the development of the leaf, and appearing on the end of the short petiole. Sometimes found on the end of a vein in a partially developed leaf, and more rarely surrounded by the lamina of the leaf. In the last case it appears on both sides of the leaf, but is most prominent above. It contains no larval cell. In size and in structure it resembles C. q. vesicula found on the same oak, but it is several weeks later and the insects differ materially. The flies appear early in June, and are of both sexes.

This species is often quite abundant in the limited space where I have found it. In describing the galls I should have added that the larva is not enclosed in a larval cell.

Habitat.--CT

Andricus pruinosus n. sp.

Galls—0.12 to 0.15 of an inch in diameter, perfectly round and variously situated on the leaves, and occasionally on the sterile aments of Q. obtusiloba [stellata]. Outside they are densely pruinose, and the walls are very thin. There is no larval cell. In many instances the blade of the leaf, or the part affected by the gall, is reduced to a mere rudiment of irregular form and varying size, but in such cases the gall is always banded by a minute ridge answering to the leaf blade. It bears a rather close resemblance to A. utriculus B.

Collected by myself on East Rock, New Haven, Connecticut, May 7?

Andricus quercusutriculus (Bassett 1881)

Hosts: Quercus chapmanii

[Asexual (a mistake? Bassett describes this as a sexual generation) generation integral leaf gall found in the spring.]