8. 



9. 



10. 



260 ERNEST A. BACK. 



f Male: front tarsi with a conspicuous dense fringe of silvery pile, 

 last two segments of the middle tarsi with a brush 

 of black bristles. Female: hind margins of the ab- 

 dominal segments white on the sides only; some- 

 times very little so 9. 



Male: front and middle tarsi without such characters. Female: 

 hind margins of the abdominal segments 2-5 alto- 

 gether white 7. 



' Scutellum convex, black; the brownish pollen at the base, if 

 any, is hardly perceptible; densely pilose with long, 

 erect pile; face in the middle with white pile 8. 



Scutellum flat, covered with dense gray pollen; longer hairs 

 along the edge only; face altogether with black hairs. 



profusus. 



Trichostical pile black montauus. 



Trichostical pile white leucozoims. 



Scutellum polished black 10. 



Scutellum with gray pollen .....plausor. 



Legs wholly black (see couplet 5) praepes. 



Hind tibiae more or less red in the middle 11. 



{Abdomen with white pile on the sides callipedilus. 

 Abdomen with black pile on the sides from the very base. 

 cymbalista. 

 f Tarsi reddish, the anterior tarsi of the male slender, honey-yellow, 

 and, together with the front tibiae, clothed above 



with not dense white pile rufotarsus. 



[ Legs not as above 13. 



( Abdomen gray, with black polished spots rattus. 



I Abdomen black, with white cross-bands 14. 



f White cross-bands on the anterior margins of the abdominal 



segments cerussatus. 



j White cross-bands on the posterior margins of the abdominal 



segments 15. 



. j Scutellum polished black; legs very hairy loiigimaiiuus. 



t Scutellum with gray pollen; legs moderately hairy 16. 



. r Trichostical pile white 17. 



\ Trichostical pile black 19. 



{First abdominal segment with a white cross-band occupying 

 nearly the entire posterior margin evidens. 

 First abdominal segment with white spots on the sides only... IS. 

 [" Wings brownish hyaline on the distal half; claws black, reddish 



at base only; length 9-10 mm rejectus. 



Wings almost uniformly hyaline, claws yellowish white, black at 

 the ends only; length 7-8 mm litigator. 



IN 



I 



I 



