J. R. MALLOCH 245 



4G. Hypopleura usuall.y with a few hairs on upper margin in front of spiracle; 

 all femora largelj' infuseated basally; palpi rufous yellow. 



texensis new species 



— Hypopleura without hairs on upper margin in front of spiracle 47 



47. Palpi rufous yellow; hypopleura bare. 



texensis variety flavofemorata new variety 



— Palpi largely or entirely black; hypopleura with some hairs in middle, just 



below spiracle limbinervis Stein 



48. Tliorax with four pairs of postsutural dorsocentral bristles; hind tibia 



with a strong bristle basad of the calcar on the posterodorsal surface; 

 some fine hairs at bases of both the notopleural bristles; prealar bristle 

 very long aberrans Malloch 



— Thorax with four pairs of postsutural dorsocentral bristles; hind tibia 



with only the calcar on posterodorsal surface; mid tibia with three or 

 four bristles on posterior surface w-hich are not arranged in a single 

 series; arista pubescent; prealar minute or absent; no hairs at base of 

 notopleurals alaskensis new species 



— Thorax with three pairs of postsutural dorsocentral bristles; hind tibia 



wuth a bristle basad of calcar on posterodorsal surface; posterior noto- 

 pleural bristle with some fine hairs adjacent to its base; hind femur of 

 male with long bristly hairs on all ventral surfaces from base to beyond 

 middle subfusca new species 



— Thorax usually with three pairs of postsutural dorsocentral bristles; hind 



tibia with only the calcar on posterodorsal surface; usually no hairs at 

 bases of notopleural bristles 49 



49. Thorax entirely, abdomen at least partly j-ellow 50 



— Thorax and abdomen largely or entirely black 52 



50. Head including antennae and palpi black; abdomen in male glossy black 



on apical half; eyes of male at narrowest part of frons separated by not 

 more than the width of third antennal segment, .nigricauda Malloch 



— Head, including antennae and palpi, largely or entirely yellow 51 



51. Eyes in male widely separated, the frons one-fourth of the head width; 



frons in both sexes largely fuscous flava Stein 



— Eyes in male widely separated, the frons one-fourth of the width of head; 



entire head in both .sexes yellow pallida (^Stcin) 



52. Scutellum partly or entirely yellow, contrasting sliarj>ly with disc of 



mesonotum 53 



— Scutellum black, concolorous with disc of mesonotum 58 



53. Ba.sal half of abdomen and the entire scutellum testaceous yellow; pre- 



alar bristle very short flavibasis Malloch 



— Abdomen entirely ])lack 54 



54. Fourth wing-vein slightly curved forward apically; fore tibia in female 



with two anterodorsal and two posterior bristles; jirealar Juristic very 

 long curvinervis new species 



— Fourth wing-vein straight or slightly deflected at apex, not curved for- 



ward; fore tibia with or without a median posterior bristle 55 



TRAN.S. AM. EXT. SOC, XLVIII. 



