On leaf, underside, generally large, sub-globular galls. Younger ones appear like older, both often being found on same leaflet, 4-7 mm. diameter. Galls covered with a fine short yellowish to reddish pubescence, suggesting the texture of peach “bloom.” Walls very thick, firm fleshy, surrounding the central spherical cavity, pierced, however, at the distal end by the fine apical canal. Closely sessile on leaf, generally at side of principal vein. Collected on _H. alba_, _glabra_ and _ovata_. From Felt’s short description, _Caryomyia antennata_ Felt, must have been taken from a similar gall. Osten Sacken, Lowe’s Mono. Dip. N. Am. Pt. I. p. 193. 1862. Beutenmuller, Am. Mus. Nat. Hist. Bull. 23:393. 1907. 18. =Cecidomyia= sp. On leaf, under side, sub-globular (almost uniformly asymmetric in that one side projects laterally so as to present a parabolic outline, rather than a semi-circular one). A short definite nipple terminates the gall. 2-4 mm. diameter. White or light yellow to red. Walls medium in thickness, of a soft, almost fleshy consistency. Exterior surface almost uniformly minutely shagreen-roughened when observed with lens. The constricted base of the gall rests in a shallow saucer-shaped structure. This gall was described from Connecticut in citation below on _H. ovata_. Rather common in Hocking County, Ohio, on _H. microcarpa_. July, August. Felt’s “Cecidomyia sp. Globose, irregular, ovate, granulate, a slight nipple, dia. 2-3 mm.” probably belongs here. Felt, Jour. Econ. Ent. 4:456. 1911. Wells, Ohio Nat. 14:291. 1914. 19. =Cecidomyia= sp. =Cecidium= nov. 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. 20. =Caryomyia caryæ= O. S. On leaf, under side, sub-spherical gall with more or less prominent apical nipple. 3-3½ mm. diameter, rarely 4 mm. Light green, turning brown, smooth. In many, very definite meridian-like striations can be observed marking the wall. Wall thin, very fragile and dry. Surface of chamber smooth as though polished. Attached by conic pedicel arising from fovea in base of gall. This pedicel with its pointed end attached to the leaf is surrounded by or rests in a cup-like structure. In this respect the gall differs markedly from No. 22, which it superficially very much resembles. Fig. 20a is a large specimen showing the peculiar interlocking base exceptionally well developed.