On leaf, under side, elongate conic, asymmetric, the axis lying
horizontal or parallel with the leaf blade plane. The tip is invariably
strongly recurved upward and backward. The side of the proximal part of
the gall lying against the leaf is flattened and rests close against
the leaf and vein; the galls always spring from the side of a vein.
Size variable from 2 mm. in length to 4 mm. this measurement distally
not being made to the tip but merely to that part of the recurved
terminal portion, farthest from the base. The larger specimens measure
1½-2 mm. in width at the proximal end. Light green to nearly white, or
sometimes roseate tinged. Very smooth. Walls thin distally thickening
toward the basal end.
Not uncommon on _H. alba_ in Hocking County, Ohio, July.
Type specimens at Ohio State University.
A gall, somewhat similar and probably a variety of the above was
collected on _H. glabra_, (Fig. 9a.)
Cylindric-conic, sharply bent over against the leaf, attenuate distal
part short, not recurved, 3½ mm. long. Smooth, white like ivory. Wall
rather thick, hard. Base of gall in shallow saucer-like depression
against the vein. Interiorly the distal end is choked with coarse
trichomes.