48 Proceedings of the Biological Society of Washington. 



Frons at vertex over half the width of head ; frontal triangle extending 

 almost to anterior margin, along its margins are a few short setulae and 

 beyond its apex on anterior margin of frons are two stronger setulae ; 

 ocellar bristles widely divergent; lower two pairs of orbital bristles in- 

 curved, upper two pairs curved outwards, between the bristles there is a 

 short setula ; antennae normal in size, second joint with distinct dorsal 

 bristle, third joint rounded, arista shorter than anterior width of frons, 

 slightly pubescent ; cheek at anterior margin about half as high as eye ; 

 diagonal series of bristles consisting of 3-4 of moderate size. Mesonotum 

 finely granulose, disc with numerous black setulae and two pairs of dorso- 

 centrals, the anterior pair rather weak ; scutellum more finely and densely 

 granulose than mesonotum, and with four marginal bristles. Abdomen 

 without hairs except on the glossy apical segment; hypopygium small, its 

 surface with a number of short setulae. Legs normal, the fore femora 

 with 3-4 bristles on the posteroventral surface. Costa with short setulae 

 to apex of first vein, both the breaks distinct, second costal division about 

 twice as long as third ; third vein ending almost exactly at apex of wing; 

 cross veins very closely approximated, not separated by more than the 

 length of inner cross vein ; last section of fifth vein three times as long 

 as penultimate section. 



Length: 1 mm. 



Type and allotype.— Vrhana, 111., Sept. 6, 1914 (J. R. Malloch). Taken 

 on a window in the basement of the Natural History Building, University 

 of Illinois. 



Separable from lacteipennis Fallen and vagans Fallen by the black frons 

 and halteres. 



