On leaf, under side, rather large conic gall, whose distal ½-⅓
constitutes a very slender apical process. Through this passes the fine
canal leading to the depressed, sub-globular chamber in the proximal
part of the gall. The galls are either erect or more generally tilted
to one side, always arising from one of the larger veins. 5-8 mm. long,
2½-3½ mm. wide at base. Outline of the flaring sessile base generally
angular. Attenuate distal portion turning dark early. Light greenish
yellow to brown when old. Smooth. Walls of chamber thick. A slender
probable variety of this is figured in 11a, pl. I.
Collected in Hocking County, Ohio, on _H. alba_. July.
Type specimens at Ohio State University.