Callirhytis nigrae

Quercus imbricaria, marilandica
Leaf galls, integral
Smooth bare elongated midrib swelling, succulent, many-celled, on under side of leaf in June.

[Photo caption]

254. On Q marilandica. Also on Q imbricaria. Adults emerged June 21-24 (DC).

Cynips quercus nigrae n. sp.

Quercus nigra [marilandica]

Irregular, elongated swelling on the under side of the midrib of the leaf.

Found two specimens, in June. One of them extends for about an inch along the vein, the other is shorter; both are greenish, and about 0.2 or 0.3 broad. Each gall contained several flies, which escaped between the 20th and 22nd of June, after which the larger gall appeared pierced with nine holes.