274 The Ohio Journal of Science [Vol. XVI, No. 7, 



The author's specimens rarely go over 3 mm. in high. 

 They vary from 2-3 mm. in width. Many are purplish tinged. 

 The chamber is sub-cylindric. rounded below. 



The protective layer is well developed and extends distally 

 as far as the inner opening of the apical canal. The nutritive 

 layer is confined to the proximal half of the chamber wall. 

 The fibro-vascular bundles pass upward close to the protective 

 layer. 



Sears, Ohio Nat. 15:384. PI. 19, Fig. 33. 1914. 



13. Cecidomyia sp. (PI. XVII, Figs. 13, 13a). 



"Leaf gall, present in great numbers on under side. A 

 "peg-shaped" gall, cylindrical when young, and developing 

 a thickened base as it grows. Pale green, straggling hirsute, 

 2-3 mm. long. Very common." Sears. 



The broad, ill-defined ridges which characterize the base of 

 this gall separates it from all others. The protective layer is 

 relatively thick, but does not extend into the wall of the distal 

 end. The nutritive layer is thin. The fibro-vascular bundles 

 pass through the parenchyma basally but approach the pro- 

 tective layer apically. 



Young specimens of this gall would closely approximate 



the gall described in Riley's report under No. 30. The expanded 



condition of the base is not gained until the gall has nearly 



completed its growth in length. 



Riley, 5th Rept. U. S. Ent., Comm. p. 612. 1890. 

 Sears, Ohio Nat. 15:384. PI. 19, Fig. 35. 1914. 



14. Cecidomyia sp. (PI. XVIII, Figs. 14, 14a). 



A large, globular, mucronate tipped gall of the stem. 5-8 mm. 

 dia. Base varies toward a truncate condition in some speci- 

 mens. Green throughout the summer; finely pubescent. 

 Chamber large, spherical. A thin membrane is constructed 

 by the larva across the distal end of the chamber. Protective 

 layer thick, nearly half as thick as the wall. Does not extend 

 to apical canal. Nutritive layer relatively thin. The fibro- 

 vascular bundles traverse the protective layer. 



Riley describes a globular gall, which on "detaching the 

 gall, the base is seen to be truncate and attached to the rib 

 of the leaf by an extremely short, conical style, which is not 

 visible from the sides. Average height, 3.5 mm., dia. at 

 middle, 3.5-4 mm." See No. 32 in Riley's fist. This gall 



