270 S. W. WILLISTON, M. D. 



pair in front, and generally they are only represented by shining 

 spots on the opaque. Only the hind tarsi are white. The female 

 has the whole distal end of the Aving hyaline. 



40. Bacclia sp. 



Allied to darapex, but smaller, the abdomen less spatulate, ap- 

 parently without the strigulie, the wings wholly hyaline at the tip 

 (for a greater distance in the female) and the axillary angle not 

 hyaline. The tibiae of the four anterior legs in the female are yel- 

 lowish at the base. Six specimens, Chapada. 



41. Bacclia clavata Fabr. 



Baccha Bubista Walker, List, etc., iii. 549 (male) ; Willistoii, Synopsis N. 



A. Syrphidse, 117, pi. iv, fig. 9. — N. Amer. 

 Baccha facialis Thomson, Eug. Resa, 504 (female). — Galapagos. 

 Spasigaster bacchoides Bigot, Ann. Soc. Ent. Fr. 1883, 326. 



Numerous specimens. It is not impossible that B. fuseiventris 

 Wied., is the female of this species. 



42. Salpingogaster nigra Schincr. 



Numerous specimens from Chapada and Rio de Janeiro. The 

 descrij)tion leaves no doubt of the identity. I observe but little dif- 

 ferences between the front tarsi in the two sexes ; in the male there 

 is a small, but distinct angulation of the hind tibias. 



43. Salpiiigoga!!»ter pygopliora Schiner. 



Two specimens, female (Rio de Janeiro) and male (Chapada). I 

 refer the two doubtfully to each other, and more doubtfully to this 

 species, but, as Schiner was in doubt himself as regards the union of 

 the two sexes he described, it is possible that they all may belong to 

 one variable species. The pleurae of the male are broadly yellow 

 and brownish yellow, the mesonotum less dark, the vertical triangle 

 shining black, and the hind femora without any dark ring. In the 

 female the thorax is as described for the male, the scutellum for the 

 female, the abdomen more of a deep brown than black, the legs yel- 

 low with the hind femora, except the tip, black, the distal part of 

 hind tibiic and the tarsi reddish yellow. In his specific descriptions 

 the second segment of the abdomen is called the first, etc. By com- 

 paring the portion bearing the mammiform processes at the base with 

 the corresponding part in Ceria, Baccha, Melanodoma, etc., it will 

 readily be seen to be the first segment. There is a very marked dif- 

 ference in the male hypopygium between this and the preceding 

 species, but similarity of structure, otherwise, is too great to distin- 

 guish them generically. 



