106 STUDIES IN AMERICAN EPHYDRIDAE (dIPTERA) 



with the mesonotum. Abdomen may said to be opaque cinereous with bases 

 of each segment more or less broadly subglabrous brown with a median pro- 

 jection to apical margin; thus forming the ever present median stripe which, 

 however, may be indistinct in some species. Sometimes the gray or brown is 

 reduced to narrow bands, and the former more or less irrorated with brown. 

 Legs normally black with bases of tarsi tawny. The males may be distin- 

 guished by having the apex of the abdomen truncate and convex. 



Notes on the Classification of the Species.- — Systematically the 

 species are very unsatisfactory, the characters of most value 

 being found in the male. By these the species may be divided 

 into two groups, based on the ciliation of the fore femora, but 

 this character shows some intergradation. However, one will 

 have little difficulty in placing this sex of the species within 

 these groups. 



Of the species of this subgenus jplumbiceps is most closely re- 

 lated to those of Phaiosterna, but is quite separate. This species 

 with fiexinervis, ciliata and texana form a distinct group, charac- 

 terized by the peculiar ciliation of the fore femora of the male. 

 In texana we have what seems to be an intermediate form sug- 

 gesting appendiculata in other respects. In the latter we have 

 one of the four species constituting what may be termed the 

 typical group; the femora here not being ciliate, and the frons 

 convex with the antennae situated well down about on a line 

 with the middle of the eyes. Another group has the femora 

 normal and frons convex, but with a silvery flattened spot on the 

 second antennal joint above. This includes the two species 

 argyrostoma and puncticornis. A third group has the frons 

 flattened and horizontal, with the antennae situated above the 

 middle line of the eyes. This group includes two species, 

 pleurivittata and taurus. The latter is somewhat of an anomaly in 

 its large heavy face with the upper parts very prominent. 



The species may be systematically arranged as follows: 



Fore femora of male ciliate beneath (fig. 7). 



Frons narrow plumbiceps 



Frons broad. 



Parafacials narrow flexineuris, ciliata 



Parafacials broad texana 



Fore femora of male not ciliate. 



Frons convex, antennae opposite middle of eyes. 

 Second antennal joint without flattened area above. 



Parafacials broad appendiculata, nigropicta 



Parafacials narrow meridionalis, brunneiceps 



