Dec, 1921 Bulletin of the Brooklyn Entomological Society 121 



2. Wings shorter than abdomen; abdomen depressed, long- 



elliptical ; front and middle tarsi elaborately developed. 



Pyrophcena.^ 

 Wings longer than abdomen 3. 



3. Front tibiae slender in both sexes Melanostoma. 



Front tibiae and tarsi of male dilated ; those of female slightly 



widened Platychirus. 



4. Long pilose species ; face protruding ; scutellum yellow ; 



squamae blackish; basal half of abdomen partly yellow 

 and greenish aeneous, clothed with yellow pile ; posterior 



half shining black and with black pile Leucosona. 



Body clothed with short pile 5. 



5. Face less than one third the width of head; mesonotum and 



abdomen rarely with yellow markings 6. 



Face usually wider than one third the width of head ; ab- 

 domen and frequently thorax with bright yellow mark- 

 ings Tribe Syrphini 7. 



6. Elongate, usually very slender, species ; eyes bare ; costa 



ending at, or slightly beyond, tip of wing. {Bacchini 



= Ocyptamus, Baccha, Salpingogaster) Baccha. 



Small, robust species with pilose eyes ; costa ending before 

 tip of wing Paragus. 



7. Sixth abdominal segment (hypopygium) of male as long as 



the two preceding ones together, cylindrical ; fifth seg- 

 ment of female one half as long as preceding. Eupeodes. 

 Hypopygium of male not protruding; fifth segment of fe- 

 male one third, or one fourth as long as preceding ... 8. 



8. Head very large, f rons inflated, surface of wings with 



scarcely a trace of villi except in subcostal cell. (Cata- 



homba) / Sc<Fva. 



Head normal ; wings clothed with villi 9- 



9. Antennae very elongate, about six times as long as broad. 



Chrysotoxum. 

 Antennae less than three times as long as broad 10. 



10. Third longitudinal vein deeply constricted into discal cell. 



Didea. 



^ Melanostoma kelloggi has Pyrophcena type abdomen but has 

 simple tarsi. 



