SCENOPINIDAE OF THE WORLD 239 



Thorax dorsum black, with transverse striations; humeral and 

 supra-alar calli red-brown; pleural areas red-brown. Wings hyaline, 

 veins brown; halter stem brown, knob red-brown dorsally, white 

 ventrally. Foreleg orange, with tarsus darkening to red-brown distally; 

 middle and hind legs orange-brown, tarsi red-brown. 



Abdomen second segment black-brown, with white lateral spots in 

 posterior membrane; remaining segments black-brown with nearly 

 equal white lateral margins. Ninth tergum concave along posterior 

 margin, ninth sternum with a sparse comb of hairs; aedeagus bilobed 

 with anteriorly directed medial spurs; see figure for details. 



Female. — Head red-brown; eyes black brown; broad postocular 

 ridge with transverse striations; frons wider than ocellar tubercle, 

 with longitudinal striations, swollen above antennal base; ocellar 

 triangle flat, set off, ocelli clear. Antennae as in male. 



Thorax dorsum black, with transverse striations, humeral and 

 supra-alar calli red-brown with orange anterior and posterior spots; 

 pleura red-brown; wings hyaline, veins brown; halter stem brown, 

 knob with a thin red-brown dorsal rib, remainder white. Legs as in 

 male. 



Abdomen second segment black-brown, granular; remaining seg- 

 ments black-brown with intersegmental membrane tan medially, 

 white laterally, eighth segment red-brown, sternum truncated; see 

 figure for details. 



Length: Male body 7.2 mm., wing 3.7 mm. ; female body 7.2 mm., 

 wing 4.1 mm. 



Type-locality: Florissant, Colorado; July 1919 (Cockerell). 



Holotype: Male (USNM) 67470. 



Allotype: Female, Florissant, Colorado; 7 July 1907 (S. A. 

 Rohwer) (USNM). 



161. Pseudatrichia concava, new species 



Figure 155 



Female. — Head red-brown; eyes black-brown, with a broad 

 postocular ridge; frons with a shallow median groove; ocellar tubercle 

 not set off, shallow; ocelli red. Antennae brown, third segment with 

 golden hairs. 



Thorax dorsum black, transversely striated; humeral and supra-alar 

 calli red-brown; scutellum red-brown; pleural areas red-brown. Wings 

 clear, veins brown; halter stem brown, knob base and dorsal rib 

 brown, remainder white. First two pairs of legs straw yellow; hind leg 

 with orange-brown femur, straw yellow tibia, tarsus yellow basally, 

 darkening distally. 



