68 Bulletin of the Brooklyn Entomological Society Vol. XVI 



(Chrysoto.vum and Sphecomyia) ; or, if the apical cross- 

 vein is upright or recurrent (Chrysogaster: small, broad, 

 black species), then the mouth is produced forward 4. 



4. The humeral calli and region between them distinctly destitute 



of pile, the head being " cupped " over the anterior end of 

 thorax, causing the pile to end abruptly behind the poste- 

 rior margin of humeral region (the head may have to be 

 removed to permit examination) ; antennae placed well 

 above middle of head ; arista usually a little shorter than 

 length of antennae; abdomen of both sexes with five visible 

 segments exclusive of genitalia ; anterior crossvein placed 

 well before middle of discal cell Syrphinae. 



- Pile extending upon the humeral region ; abdomen of males 



with only four visible segments exclusive of hypopygium, 

 females with five 5. 



5. Apical crossvein recurrent at distal end; marginal cell closed; 



arista with either long or very dense plumosity; face pro- 

 truding downwards ; wings broad ; alula very broad ; 

 squamae usually very broad; thorax frequently bearing 

 bristles Volucellinae. 



- Apical crossvein parallel with wing margin, or, if recurrent 



(Chrysogaster, Eumerus and Merodon), the arista is 

 bare 6. 



6. Arista long plumose for at least the greater two-thirds of its 



length ; marginal cell open ; anterior crossvein placed near 

 or beyond middle of discal cell; either yellow markings 

 present on abdomen, or with dense pile more or less yellow, 

 except Pyritis, which has long dense brownish pile ; face 

 protruding downwards, or swollen, or tuberculate; the 

 right prong {or style, Met calf) of the forceps of the geni- 

 talia is longer than the left one and tapers to a sharp point, 

 the left prong developed as an obtuse lobe. . Sericomyinae. 



- Arista rarely long plumose for one-half its length or more, in 



such cases some (certain species of Eristalis) may be ex- 

 cluded by the closed marginal cell; others (certain Chi- 

 losia) can be excluded by the absence of yellow body mark- 

 ings or yellow pile, and by having the anterior crossvein 

 placed well before middle of discal cell ; finally, the prongs 

 of the genitalia are similar 7. 



7. Very large yellow and black species ; the post stigma very 



elongate, being very nearly twice as long as broad; mar- 

 ginal cell closed ; third vein with a downward loop into 

 discal cell ; sixth vein recurrent beyond anal cell ; shape of 



