Collected in Athens County, Ohio, on H. alba, August.
Type specimens at Ohio State University.
9. Cecidomyia sp. Cecidium nov.
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.
10. Cecidomyia sp. Cecidium nov.
Leaf, under side, distal ⅔ of gall dome-shaped with 3-many triangular sides, the flaring base resting on the proximal, constricted or saucer-shaped ⅓; 2-3 mm. high, 3-4 mm. wide. Tip attenuate, not sharp pointed, however. Light green to yellowish green, the tip darker, reddish to black. Surface smooth under lens. Larval chamber spherical, surrounded by sclerenchmya layer. This gall is very distinctive no other forms having the peculiar angular structure which it possesses. Not abundant.