NO. 13 



STAPH VLINIDAE- — BLACK WELDER 



85 



great modifications of the posterior border of both these sclerites. In 

 Tachinus^the tergite (fig. 29 G) is divided into three lobes. The two 

 outer ones are slender, and each bears a very long seta at its apex. 

 The median process is semicircular but produced into a sharp point at 

 the middle. In other species this median process may be much longer 

 than the lateral ones, or it may itself be bifid or even trifid. The 



Fig. 30. — Intrafamily variation in the genitalia of the female 

 (continued from fig. 29). 



A, Micropeplus punctatus Lee; B, Stenus sculptilis Csy. ; C, Piiwphilus parvi- 

 pennis Csy.: D, Paedenis lactiis Er. ; E, Alcochara lata Grav. ; F, Psciidopsis 

 oblitcrata Lee. All ventral aspects. 



sternite is even more highly modified in TachUius (fig. 29 F). The 

 border is divided into six lobes of about equal length, but considerably 

 shorter than the lateral lobes of the tergite. The outer pair on each 

 side are rather slender, and each bears a long seta at the apex. The 

 two median lobes are wider, and each bears a brush of six very 

 straight short setae. 



The ninth tergite and sternite are said to be nearly always mem- 

 branous (Tanner. 1927). The only exceptions recorded by him are 



