FAMILY SYRPHID.K THE FLOWER FLIES 263 



79. Face broadly carinate, convex in profile Ceriogaster Williston 



Face concave or more or less tuberculate SO 



80. Face produced somewhat downward and weakly tuberculate (60, 63, 



64 ) *Cynorhina Williston 



Face concave, not tuberculate 81 



81. Abdomen with yellow pollinose fasciae 82 



Abdomen brassy, with opaque black fasciae (119, 128). 



fChrysosomidia, n. g. 



82. Posterior femora with a tooth-like projection below near the apical 



end Spilomyia Meigen 



Posterior femora simple (21, 22, 132). 



JTemnostoma St. Fargeau and Serville 



83. Posterior femora with a bifid spur below; face concave, subcarinate 



(121, 131) Senogaster Macquart 



Posterior femora without such spur 84 



84. Posterior femora very greatly swollen, never with a triangular 



preapical protuberance, though usually spinose; head almost cir- 

 cular, the cheeks linear (28, 133, 134). .Syritta St. Fargeau and Serville 

 Posterior femora much less swollen; head not globose 85 



85. Posterior femora with a small, toothlike projection below toward the 



apex§ (20, 122) Milesia Latreille 



Posterior femora not toothed, sometimes with a triangular process 

 apically 86 



86. Posterior femora with a triangular projection apically (19, 36, 135). 



UTropidia Meigen 

 Posterior femora without such process 87 



87. Posterior femora strongly swollen and strongly arcuate, their tibiae 



with a median internal spur in the male (136, 137). 



Teuchocnemis Osten Sacken 

 Posterior femora much less swollen and but little curved; tibiae 

 simple; mesonotum ochraceous pollinose (138) Pterallastes Loew 



88. Abdomen wdth pale spots or fasciae 89 



Abdomen without pale spots or fasciae, rarely reddish in ground color 



beneath thick reddish pile on the second segment 90 



89. Posterior calli with short, stout bristles; abdominal spots more or 



less orbicular Condidea Coquillett 



Posterior calli without bristles; abdomen with narrow pale fasciae 

 at least beyond the second segment (16, 33, 139) . . ||Sericomyia Meigen 



90. Face very broad and swollen; body pile almost unicolorous. 



Pyritis Hunter 

 Face not unusually broad; pile bicolored (15, 144) Arctophila Schiner 



91. Marginal cell closed and petiolate 92 



Marginal cell open 95 



* Curran. 1924, Can. Ent. Ivi, p. 195. 



t Shannon, 1916, (Calliiirobola) . Pr. Ent. Soc. Wash., xviii, v. 109. 



t Curran, 1930, Bull. Amer. Mus. Nat. Hist., Ixi, p. 72. 



§ Absent in some Oriental species. 



H Shannon, 1926, Pr. U. S. N. M., Ixix, Art. 9, p. 9. 



!| Curran, 1934, Amer. Mus. Novit. No. 724, p. 6. 



