44 NORTH AMERICAN DIPTERA. 



2. Face projcctintj on oacli side in a rounded, conical protuberance, thickly 



covered with hair Glutops Burgess. 



Face with two deep diverging furrows, running from the base of the 

 antenna* to the oral margin. . . . AKTriROCKUAS Williston. 



LEPTINiE. 



1. Front tibia; with terminal spurs 2 



Front tibiae without terminal spurs o 



■ 2. Front tibiae with a single spur; sometimes only four posterior cells pres- 

 ent in the wing. Dialysis Walker. 



^ ^ . Front tibia? with two spurs ; five posterior cells as usual. 



t^li OA^ Triptotbiciia Locw. 



o. Third joint of the antenn;e round, oval or pear-shaped, its bristle dis- 

 tinctly terminal. ......... 4 



Third joint of the antennffi kidney-shaped, the arista 7nore dorsal. 



4. Anal cell open ; hind tibia* with two spurs. . Leptis Fabricius. 

 Anal cell closed 5 



5. Third joint of the antennae with a slender arcuate bristle; hind tibiae 



with one spur. ..... Chuysopila Macquart. 



Third antennal joint with a shorter, slender style. 



^^ j Spania Meigen. 



^ -^PTiOfamA Zetterstedt. 



0. Hind tibia* with two spurs; anal cell closed. . Athkrix Meigen. 



Hind tibia? with a single spur; anal cell open. 



Syaiphoromvia Frauenfeld. 



14. STPvATIOMYIDiE. 



Small to moderately large, nearly bare or thinly pilose, bris- 

 tleless species. Head short, hemispherical or flattened, as 

 broad as the thorax. Ocelli present. Eyes contiguons or 

 separated by the front in the male. Antennae porrect, approx- 

 imated at the base, three-jointed, the third joint always com- 

 plex, nsnally with a terminal style or an arista. Pi'oboscis 

 never elongated ; palpi two or three-jointed, sometimes rudi- 

 mentary. Thorax never strongly convex ; scntellnm often 

 with tubercles, spines or projection on its margin. Abdomen 

 composed of from five to seven segments, nsually flattened. 



^U^.ri Sj^i 



