Andricus (Callirhytis) pilula, n. sp.

Small, round, thin-shelled galls on the blade of the leaves of Q. undulata, collected in southern Utah by Mr. Siler. They are usually situated near the margin of the leaves and always on one of the principal leaf veins, and project equally above and below the surface. The average size is only .15 of an inch in diameter. The galls resemble those of Neuroterus utricula Bass, more nearly than any other species known to me. I found twenty-five or thirty specimens in a box of A. Sileri, and was so fortunate as to find two of them that, though perforated, still contained the gall-flies. These were both females, quite perfect, and the description that follows will, no doubt, well agree with more recent specimens.

- HF Bassett: (1890) New Species of North American Cynipidae (1890)^©

Reference: https://www.biodiversitylibrary.org/item/32322#page/85/mode/1up