Dec, 1915] Zoocecidia on Species of Hicoria 55 



center of which arises a well defined nipple. Dia. across top, 

 21/^ 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 develop- 

 ment appear to burst through the epidermis, for gall is sur- 

 rounded by the ragged collar-like remnant. The rounded 

 proximal end strongly sunken in the leaf blade which is prom- 

 inently 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 \]/2 mm. wide. Gall projects from 

 leaf surface 1-13^ 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, partic- 

 ularly toward the periphery. At first it was thought that this 

 gall might be a juvenile form of H. tubicola, but later observa- 

 tions 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. 



The author has collected this interesting gall at Gypsum, 

 Ohio, in August. Many of them measured 5 mm., not including 

 the radiate, bract-like processes borne on the flaring rim of the 

 gall. The galls bear an evanescent thin disk of tissue on the 

 distal, central region, which is clear brown in color and bears 

 erect scattered trichomes. The underlying surface of the gall 

 or the outer convex part is perfectly smooth. The origin of the 

 apical, brown disk is problematical; from the material at hand 



