214 NORTH AMERICAN DIPTERA 



47. Costa with setulae (13) Oreothalia Melander 



Costa without setulae (6, 33) Heleodromia Haliday 



48. Auxiliary vein obsolete apically (42) Proclinopyga Melander 



Auxiliary vein ending in the costa 49 



49. Cheeks very wide Roederio/des Coquillett 



Cheeks narrow 50 



50. Body shining or sub-shining Dolichocephala Macquart 



Body opaque 51 



51. Face not prominent below; no acrostical setae (44, 64). . .Clinocera Meigen 

 Face prominent below; acrosticals present or absent (43, 62) 



Wiedemannia Zetterstedt 



52. Style shorter than the third antennal segment 53 



Arista more than twice as long as the third antennal segment (47, 66). 



Chelipoda Macquart 



53. Humeral crossvein absent 54 



Humeral crossvein present (26) Chelifera Macquart 



54. Discal cell closed apically Colabris Melander 



Discal cell open apically (15) Hemerodromia Meigen 



55. Thorax very elongate, the humeri large; proboscis slender and not 



tapering 56 



Thorax more robust, the humeri rarely large; proboscis thick basally 

 and more or less strongly tapering 58 



56. Anal crossvein completely absent 57 



Anal crossvein present (16, 18) Tachypeza Meigen 



57. Front narrow, its sides nearly parallel (54, 61) Tachydromia Meigen 



Front V-shaped, wide above (65) Tachyempis Melander 



58. First basal cell equal to or longer than the second 59 



First basal cell decidedly shorter than the second 64 



59. Legs with strong bristles 60 



Legs without conspicuous bristles 62 



60. Wings about one-third noi^mal length (32) Thinodromia Melander 



Wings as long as the abdomen 61 



61. Two pairs of presutural dorsocentrals (8) Coloboneura Melander 



One pair of presutural dorsocentrals (46, 56) Chersodromia Walker 



62. Eyes bare 63 



Eyes pubescent Megagrapha Melander 



63. Arista apical Charadrodromia Melander 



Arista dorsal Micrempis Melander 



64. Anal cell entirely absent 65 



Anal cell partly formed (49, 50) Platypalpus Macquart 



65. Arista dorsal (58) Stilpon Loew 



Arista apical or subapical (19, 20) Drapetis Meigen 



