212 R. E. SNODGRASS. 



is a slender club-shaped lobe (A). The second (B) has the typical 

 form of a wide plate ending distally in a point turned forward, and 

 having all but the terminal part of the anterior margin reflected ex- 

 ternally upon itself as a narrow lobe with free edges. The third 

 (C) is smaller, triangular, and arises from the outer side of the base 

 of the second! 



Tipiila acuta Doane (PI. XV, figs. 112. 11.3, 115, 116, 117). 



The eighth sternum is enlarged and projects prominently beneath 

 the hypopygium. Its posterior margin is concave and bears mesi- 

 ally two wide, crossed brushes of hairs (fig. 113). On each side 

 there is ^articulated to it a wide appendicular lobe ending in three 

 large blunt processes. 



The hypopygium is of ordinary form, and consists of a distinct 

 tergum, pleura and sternal plates. The t.ergum (fig. 117) is a wide 

 plate with both anterior and posterior margins concave. On the 

 posterior margin are two median triangular points. From the pos- 

 terior angles of the sternum there project downward two slender 

 arm like appendages (fig. 115). 



The three apical appendages are simple. The first is flattened 

 and clavate, the second largest and triangular, the third is small and 

 attached to the base of the second. 



The guard of the penis (fig. 116) is flattened and somewhat de- 

 curved. Just beyond the base it contracts to a narrow stalk, beyond 

 which it rapidly expands into a wide triangular plate, having the 

 distal edge produced into a median and two lateral triangular lobes. 

 A deep groove traverses the entire length above. 



'ripiila sequalis Doaue (PI. XIII, figs. 78, 79). 



The eighth sternum is rather large and is deeply emarginate on 

 its posterior border. From the apex of the notch there diverge 

 downward and posteriorly two long slender brushes of hairs. From 

 each lateral angle of the notch there arises a short conical lobe 

 attached by its apex (fig. 78, a). Its distal flat end is triangular 

 and concave, and the outer angle is produced into a large, strong, 

 inwardly curved hook. In this character this species closely resem- 

 bles T. inermis. 



The tergum of the hypo})ygium is almost divided by a deep me- 

 dian notch. The sternum has the ordinary form, being deeply cleft 

 niesially, with the two lateral ])lates united by a narrow bridge of 



