296 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



(11) { 



ScutellumsMning black; legs very hairy. -9. longimanusJjw., $ ?. 

 Scutelliim with gray pollen; legs moderately hairy, (12) : 

 ( The fan-like fringe of hairs in front of the halteres is white, (13) : 

 (1^) \ The fan-like fringe, etc., is black, (15) : 



5 First abdominal segment with a white cross-band, occupying 

 nearly the whole posterior margin 11. evidens n. sp., ^ ?. 

 ^ First abdominal segment with white spots on the sides only, (14) : 



C Wings brownish-hyaline on the distal half; ungues black, reddish 



..." at the base only ; length 9-10>^ 12. rejectus n. sp., 9 . 



( ^ ) Wings almost uniformly hyaline; ungues yellowish-white, black 



I at the ends only ; length 7-8'"'^ 13. nugator n. sp., ( <? ?) 9 . 



( Front and face broad, with a hoary bloom . .15. sudator n. sp., $ ? . 

 (15) } Front and face rather narrow, the bloom upon them not hoary, 

 / 14. positivus n. sp., $. 



.^r.. ( Tibife black, (17) : 



( ^^1 \ Tibiae, except the tip, red 6. aurifex n. sp., $ ? . 



,„. ( Scutellura black, shining, (18) : 

 ^ ' \ Scutellum with gray pollen 8. cretaceus n. sp., 9 . 



f Hairs on the face black, mixed with some white (compare lojigi- 



I manus Lw.). 



(18) <J Hairs on the face yellowish; front tarsi of the male unusually 



I long; front and hind tarsi with silvery hairs on the upper side, 



) T.princeps n. sp., $. 



1. CTRTOPoaoN CALLIPEDILUS Loew, Berl. Ent. Zeit., 1874, 358, ^ ?. 

 — 3Iale. — Black ; thoracic dorsum with a very weak brownish pollen, form 

 ing an indistinct geminate stripe in the middle and some ill-defined 

 marks on the sides ; long white pile on the face, the lower part of the 

 occiput, front part of the chest, fore coxie, and the sides of the two first 

 abdominal segments ; black pile on the remainder of the abdomen and 

 the top of the head ; some scattered black hairs on the thorax above 

 and some black hairs in the mystax above the mouth. Femora black 

 with long, soft, white pile ; tibise reddish, beset with blackish pile ; tarsi 

 black, except the first joint of the four hind tarsi, which is often reddish 

 to a greater or less extent from the root ; the front tarsi, beginning 

 with the second joint, are densely beset on their upper side with, recum- 

 bent, short, silvery hairs, parted in the middle ; the under side of the 

 same joints is densely beset on both sides with short, black bristles ; 

 the two last joints of the middle tarsi have on each side a dense, flattened 

 tuft of black bristles, which form together a kind of disk, which is a 

 little broader than long. Wings grayish-hyaline, more hyaline on the 

 proximal half. 



Female. — Head, and especially the face, covered with a dense whitish - 

 gray pollen; the thoracic dorsum covered with a brownish-gray pollen, 

 completely concealing the black ground-color, except at the four corners 

 and on the scutellum, which is black and shining ; a geminate darker 

 line in the middle of the dorsum, not reaching the scutellum ; pleurae 

 likewise clothed with dense j^ellowish-gray pollen. Abdomen shining 



