On leaf, under side, sub-globular with minute apical nipple. Tip of latter truncate with fine pore in center. 3 mm. high, 2½-3 mm. wide. Generally wider through one axis. Smooth; light greenish yellow. Interiorly a more or less prominent nipple projects inward from the distal end of the chamber, traversed by the apical pore. Toward maturity the interior wall is reddened. Gall attached by a short, cylindric pillar, extending from the leaf into the base of the globular structure. At the end of summer the galls fall from the leaf, leaving this pedicel on the leaf. Galls when found are apt to occur in large numbers, as many as 50-60 commonly being found on a single leaflet. Collected in Hocking County, Ohio, on _H. microcarpa_, July. Type specimens at Ohio State University. 23. =Cecidomyia= sp. =Cecidium= nov. (?) Leaf, under side, depressed (door-knob-shape) closely sessile on leaf attached by a very short stout pedicel. 3-4 mm. wide, 2-2½ mm. high. Greenish to dull brown, covered with short, thin pubescence or smooth. Interiorally from both the proximal and distal sides, truncated, conic processes extend inward, meeting in the center. From the end of the upper one numerous, very coarse trichomes radiate into the gall chamber, which are white at first, turning brown. The central tissue and the walls are of a firm, fleshy character. There is commonly a more or less definite fovea, exteriorly at the distal end. Collected in southern (Hocking County) and northern (Lake County) Ohio on _H. ovata_. Thompson briefly describes and illustrates a gall similar to the above which Felt as editor called _Caryomia thomsoni_. The illustration, however, shows the gall not be to Felt’s _C. thompsoni_ as he has described it, viz., “Globose, with long, erect, reddish, fuscous hairs.” Felt, Bull. Brooklyn Ent. Soc. 8:99. 1913. Thompson, Illus. Cat. Am. Ins. Galls, p. 56, pl. 12, Fig. 227. 24. =Cecidomyia= sp. =Caryomyia similis= Felt (?) On leaf, under side, large, globular, 4-5 mm. dia. Light yellow-green to brown, surface puberulent. A minute nipple terminates the gall. Walls thin. Attached by a short pillar, over which the basal part of the sphere fits like a cap. Surface of leaf not noticeably raised on side opposite the gall. Collected on _H. microcarpa_ in Ohio and _H. glabra_ in Connecticut. This gall is very close if not identical with _Caryomyia similis_ Felt. It differs from his description in that it is not “depressed.” Felt, Jour. Econ. Ent. 4:456. 1911. Felt, Bull. Brooklyn Ent. Soc. 8:99. 1913. 25. =Cecidomyia= sp.