Cynips weldi sp. nov.

Gall: On the underside of the petiole of the leaf of white oak (Quercus alba) at the junction of the leaf blade, July to October. A rounded ball-like cluster of bright red or brownish galls closely pressed together and out of shape. The individual gall is rounded or tuberculated on the summit, flattened at the sides and pointed at the place of attachment. It is solid when fresh with a single barely visible larval chamber in the center. Late in September and in October the galls become detached, drop to the ground and the larvae continue to feed therein. The gall gradually changes its shape and becomes subtriangular or polyhedral and may be taken for that of another species. The outer shell becomes thin, soft, darker in color, and the inner part is eaten away until only a hard and woody shell remains. Diameter of clusters 8-20 mm. Individual galls 5-10 mm.

Range: Ithaca, NY; Glencoe, IL; Boston, MA; NY and NJ

The late Miss Cora H. Clarke sent me a lot of the galls of this species collected late in September, 1914, which did not produce adults before March (indoor), 1916, and Mr. Weld has had adults issue the second, third and fourth years. It is allied to C. nigrescens.

- William Beutenmuller: (1918) Two New Cynipidae^©

Reference: https://www.biodiversitylibrary.org/page/30313791#page/168/mode/1up