188 K. B. 8NODGRASS. 



genital chamber is a wide open cup shaped invagination of the pos 

 terior face of the segment. 



The tergal part of the hypopygium is prolonged posteriorly be 

 yond the lateral parts as a quadrate lobe with the caudal margin 

 emarginate. The pleural lobes are large, convex outwardly, slightly 

 narrowed at the distal end and roundly truncate. Two apical ap- 

 pendages arise from the inner face of each pleurum near its distal 

 end. The more dorsal one is short and spatulate, and has a strong 

 sharp hook arising from its base. The inferior one is a long, slen- 

 der, strongly chitinous, tapering, knife like blade. Both are direc- 

 ted inward and forward. 



The guard of the penis is plate-like. The second gonapophyses 

 are forked appendages arising above the guard from the sides of 

 the genital chamber. 



Trimicra anomala O. S. (PI. VIII, fig. 9). 



The hypopygium of this species is very similar to that of the last. 

 The pleural plates, however, are larger and give a more expanded 

 appearance to the end of the abdomen. 



The tergal part of the hypopygium is somewhat produced poste- 

 riorly as a truncate plate (fig. 9). The sternal margin is entire and 

 slightly convex. There are no sutures between the tergum and 

 sternum". The pleura are very large oval lobes, strongly convex on 

 all sides, and widely divergent (fig. 9). One large curved finger- 

 like process, with a sharp and strongly chitinized tip, projects 

 inward and forward from the apex. 



The guard of the penis (fig. 9, p, g) is an elongate triangular pro- 

 cess, grooved above, arising from the floor of the genital chamber 

 and mostly projecting out of the latter posteriorly. 



The second gonapophyses (fig. 9, gon. 2) are strong hooked pro 

 cesses arising from the walls of the genital chamber above the base 

 of the guard. 



Symplecta punctipennis Meigen (,P1. VIII, figs. 10, 12). 



The abdomen is slender. The body of the hypopygium is nar- 

 rower than the preceding segments, but the flaring pleural lobes 

 stand out prominently at the end of the abdomen. The eighth seg- 

 ment is very short (fig. 12). 



The body of the hypopygium is ring like, with no sutures between 

 tergum and sternum. The sternal part is concave on the posterior 



