Belonocnema fossoria [not a formal synonym per Zhang but Weld uses this name to cover leaf galls of this genus on both Quercus virginiana and geminata. The former is B treatae.]

Quercus virginiana, geminata
Leaf galls, detachable
Tan, smooth, globular galls on under side of leaf in numbers in the fall.

[Photo caption]
Fig 230. On Q virginiana. Also on Q geminata. Adults emerged 8-13. In two cases where the galls were numerous on the leaves in the fall shriveled old galls of Belonocnema treatae Mayr were found on the roots.

- LH Weld: (1959) Cynipid galls of the eastern United States^©

Reference: https://www.biodiversitylibrary.org/item/273718#page/125/mode/1up