FAMILY MUSCID.E 389 



20. Cheeks usually less than one-third the eye-height; face as long as the 



front or nearly so 21 



Cheeks more than half as wide as the eye-height; face shorter than 

 the front, slightly retreating below; intra-alar bristles absent; 

 scutellum with four bristles Gimnomera Rondani 



21. First vein bare 24 



First vein setulose on apical portion 22 



22. Scutellum with six bristles Bucephalina Malloch 



Scutellum with four bristles 23 



23. Palpi strongly widened and spatulate *CordylurelIa Malloch 



Palpi but little widened Megaphthalma Becker 



24. Anal vein extending to the wing margin 26 



Anal vein not reaching the wing margin 25 



25. Third antennal segment four times as long as wide. Micropselapha Becker 

 Third antennal segment less than three times as long as wide. 



Cordylurella Malloch 



26. With two or more rows of acrostical hairs 27 



Without acrostical hairs Cordilura Fallen 



27. With more than two rows of acrostical hairs (57) . . .Ceratinostoma Meade 

 With only two rows of acrostical hairs Opsiomyia Coquillett 



28. Third antennal segment angulate at upper apex 29 



Third antennal segment rounded apically 33 



29. Acrostical setae in two rows 30 



Acrostical setse in several rows (34) Spaziphora Rondani 



30. Anterior tibiae clothed beneath with dense, black setulae 31 



Anterior tibiae not clothed beneath with dense, black setulje 32 



31. Male wing broadly emarginate between the fourth and fifth veins. 



Pleurochaeta Becker 

 Male wing normal in outline Pogonota Zetterstedt 



32. Palpi spoon shaped, narrow basally Pseudopogonota Malloch 



Palpi broad, tapering basally but the base broad. . . .Trichopalpus Rondani 



33. Mesopleura with an extensive bare area above the anterior coxae.... 34 

 Mesopleui-a haired on almost the whole surface (33). .Scopeuma Latreille 



34. Fourth vein strongly approaching the third at the wing-tip. 



Lasioscelus Becker 

 Fourth vein not strongly approaching the third apically 35 



35. Anterior tibiae without dense, short setulae beneath 36 



Anterior tibiae with dense, short setul« beneath. ... Microprosopa Becker 



36. Anal vein almost reaching the wing margin (39) Achaetella Malloch 



Anal vein not nearly reaching the wing margin ; 37 



37. Arista plumose or very long pubescent Parallelomma Becker 



Arista pubescent Americina Malloch 



* Curran, 1929, Can. Ent., Ixi, p. 133. 



