100 NORTH AMERICAN DIPTERA 



Postnotum with, bristles; An ending well beyond base of cubital fork; 

 posterior pronotal bristles usually absent; spiracular bristles present 

 (except in Limatus) (Neotropical) 35 



32. Spiracular bristles absent; clypeus normal 33 



Spiracular bristles present (one or more); clypeus rather small and 



narrow; cell R- longer than its stem 34 



33. Cell R2 shorter than its stem; several posterior pronotal bristles; wing 



scales normal Zeugnomyia Leicester 



Cell R2 longer than its stem; two posterior pronotal bristles; wing- 

 scales emarginate at tips Hodgesia Theobald 



34. Proboscis very hairy, much enlarged at tip Harpagomyia de Meijere 



Proboscis not hairy, rarely enlarged at tip Topomyia Leicester 



35. Middle legs with "paddles" formed of very long erect scales. 



Sabethes Desvoidy 

 Middle legs without "paddles" 36 



36. Clypeus with hairs; large species with long palpi. 



Trichoprosopon Theobald 

 Clypeus bare, or with scales only 37 



37. Hind tarsi with long suberect scales; large species with long cT palpi. 



Goeldia Theobald 

 Hind tarsi with appressed scales only; smaller species with short o' 

 palpi 38 



38. No bristles on subalar knob; pronotal lobes large and almost in con- 



tact; mesonotal scales all metallic Sabethoides Theobald 



Bristles present on sub-alar knob; pronotal lobes more widely sepa- 

 rated; mesonotal scales rarely metallic 39 



39. Spiracular area with scales only; hind tarsus with one claw. 



Limatus Theobald 

 Spiracular area with 1-4 bristles, no scales; hind tarsus with two claws. 



Wyeomyia Theobald 



