Gall (p. 17, fig 15). —A bare, smooth ellipsoidal gall, 5.0 mm. long by 2.9 mm. in diameter with a nipple at the apex, protruding from a shallow depression in the side of the acorn cup and dropping to the ground when mature in late summer, and then showing a girdle of hairs at the base. From one to eight on an acorn. Monothalamous.

- LH Weld: (1952) New American Cynipid Wasps From Galls^©

Reference: https://www.biodiversitylibrary.org/page/15672479#page/375/mode/1up