On leaf, under side, small, smooth, spherical galls, with a peculiar
tip shaped like the end of a bottle, arising abruptly from the globular
gall, 2-2½ mm. diameter. The gall reminds one of a miniature bomb.
Green to yellowish with dark spots over the distal half. Thin-walled.
Attached by a minute obconic pedicel. The pupa in these galls is
suspended in the upper part of the chamber by a thread passing from
each end of the body to the walls of the chamber. The galls drop from
the leaves in late July. Not common.
Collected in Hocking County, Ohio, July, on _H. microcarpa_.
Type specimens at Ohio State University.