On leaf, under side, rather large, pouch-like gall (5-6 mm. long) arising from a principal vein. Shaped like a stout gourd, it is bent over nearly recumbent against the blade of the leaf. 2-2½ mm. wide. The proximal end is sharply constricted at the minute point of attachment. The walls when collected were light brown in color, sparsely covered with short white hairs. Walls very thin and when dry brittle. Interior surface smooth. Inconspicuous on the upper side of the leaf, except for the minute pore next the vein. Two specimens from the same leaflet. This gall differs so markedly from all the other cecidomyidous galls of the hickories, that I am not certain just where to place it. They contained no occupants of any kind. Collected in Hocking County, Ohio, on _H. glabra_, July. Type specimens at Ohio State University. 30. =Cecidomyia= sp. =Cecidium= nov. On leaf, under side, obconic gall resting in firm collar-like base. Somewhat similar to 31, but differs in definite constant characters to make it distinct. Proximal end not rounded but definitely conic, distal broad end with prominent fovea in the center of which arises a well defined nipple. Dia. across top, 2½ mm., height from leaf surface, 2 mm. Greenish to reddish brown, smooth. No prominence or convexity of leaf surface opposite the gall, a slight discoloration only marking the position of the cecidium. Collected in Hocking County, Ohio, on _H. microcarpa_, July. Type specimens at Ohio State University. 31. =Cecidomyia= sp. =Cecidium= nov. On leaf, under side, small, obconic galls which in development appear to burst through the epidermis, for gall is surrounded by the ragged collar-like remnant. The rounded proximal end strongly sunken in the leaf blade which is prominently convex on the opposite side. Distal end truncate with funnel-like depression leading to the rather large apical pore. This latter connects the depressed chamber within with the exterior. Distal broad end 1½ mm. wide. Gall projects from leaf surface 1-1½ mm. Smooth; light greenish-yellow in color. Walls very thick distally, very thin proximally where it is connected to the leaf at the central region. On the upper side of the leaf the low, hemispheric convexity is reddened, particularly toward the periphery. At first it was thought that this gall might be a juvenile form of _H. tubicola_, but later observations have shown it to grow no further in length. It is without doubt distinct and new. 32. =Cecidomyia= sp. “Leaf-gall on under surface, having the form of a much depressed inverted cone, attached by its apex, and with the free base surrounded by a conspicuous fringe. 3-4 mm. high, 4-5 mm. in diameter. Green to light yellow-green. Huron, July 25. Quite rare and I believe hitherto unreported.” Sears.