362 



ment and entire dorsum of other segments; venter yellowish. Legs 

 yellow, mid and hind tibiae with a brownish black spotlike mark on 

 dorsal surfaces near base. Wings with a large black mark covering 

 the entire area anterior to third vein from middle of second to apex of 

 third and extending slightly posterior to third near its apex; veins 

 black. Halteres yellow. Setulose hairs on head and thorax black, the 

 weak hairs pale yellow. 



Frons over one third the head-width, triangle poorly defined ; an- 

 tennae small, third joint rounded apically, slightly pilose; arista short- 

 haired; cheek linear; eyes sparsely haired. Surface of mesonotum 

 with weak hairs; apical pair of scutellar bristles distinctly stronger 

 than basal. Abdomen rather slender; hypopygium of moderate size, 

 recurved. Legs normal. Third costal division of wing about three 

 fourths as long as second ; veins 3 and 4 parallel, the latter ending in 

 wing tip. 



Length, I mm. 



Type locality, Urbana, 111., July 4, 191 5, at rest on cypress limb 

 (J. R. Malloch). 



Differs from any described species of the genus in the wing mark- 

 ings. 



Gaurax pallidipe:s, n. sp. 



Male. — Black, shining. Head yellowish brown; frons opaque 

 black-brown, triangle glossy black ; antennae brownish ; arista fuscous ; 

 palpi dusky yellow ; back of head black. Thorax and abdomen shining 

 black, the latter slightly yellowish at base. Legs entirely yellow. 

 Wings with a very distinct infuscation on anterior basal half, which 

 fades out before apex of third vein; veins black. Halteres yellow, 

 knob black. Hairs and bristles on head black; bristles on thorax yel- 

 low ; hairs on thorax and abdomen white. 



Head short and broad ; frons one half the width of head, triangle 

 well defined and very large, filling almost the entire frons ; lateral and 

 vertical setulae strong; antennae large, third joint very hairy; arista 

 slender, short-haired; marginal hairs on cheek strong; eyes very dis- 

 tinctly haired. Mesonotum rather densely covered with long white 

 hairs ; scutellum with similar hairs and 4 marginal bristles, the apical 

 pair strongest. Abdomen short and broad. Legs of moderate strength. 

 Third costal division of wing two thirds as long as second ; veins 3 and 

 4 parallel, the latter ending in wing tip. 



Length, 1.5 mm. 



Type locality, Urbana, 111., July 4, 191 5, at rest on cypress limb 

 (J. R. Malloch). 



