inse;cutor insciti^ menstruus 121 



definitions of the genera 



Chrysogaster Meigen : Certain males (e. g., nigripes, texana, 

 greeni, infMtifrons, nigripennis, versipellis, chilosioides) have 

 a small inconspicuous facial tubercle. Frons and a patch on 

 each side of face faintly rugulose ; eyes bare ; face with scat- 

 tered pile ; lower posterior edge of scutellum without downward 

 projecting pile (present in chilosioides, nigripennis, versipellis, 

 and alaskensis) ; outer edge of scutellum tends to be marginate ; 

 dorsal surface of abdomen flattened, opaque, the sides shining; 

 the petiole beyond the union of the third and fourth veins 

 longer than length of discal cell; thorax without bristles. 



Callicera Panzer : Antennae very elongate, bearing a terminal 

 style (in others of this group the antenna is of normal length 

 and bears a dorsal arista) ; eyes, face and upper surface of 

 squamae pilose ; lower posterior edge of thorax with downward 

 projecting pile ; face inconspicuously tuberculate, thorax with- 

 out bristles. 



Ferdinandea Rondani : General color brassy ; eyes and face 

 pilose ; thorax with numerous bristles ; discal cross- vein joining 

 discal cell at or beyond middle; lower posterior edge of scu- 

 tellum with downwardly hanging pile ; lower sides of tarsi 

 without short bristles ; petiole of third and fourth veins as 

 long as discal cross-vein. 



Chilosia Meigen : Both sexes with prominent facial tuber- 

 cles; eyes hairy; face bare (subgenus Chilosia); face hairy 

 (new subgenus Chilomyia, type occidentalis Will.) ; a dis- 

 tinctly chitinized projection of the face proceeds upward be- 

 tween the antennae to meet a downward projection of the 

 frontal lunule, thus separating each antenna and enclosing each 

 with a chitinous rim ; thorax usually with bristles ; scutellum 

 not marginate, the lower posterior edge with abundant down- 

 ward projecting pile ; discal cross-vein placed well before middle 

 of discal cell ; petiole beyond union of third and fourth veins 

 as long as length of discal cross-vein. 



Cartosyrphus Bigot : Differs from the above in having eyes 

 and usually face bare ; antennal pits confluent. Subgenus 



