30 THOMAS SAY FOUNDATION 



It differs from meigenii in practically nothing 

 but the more broadly expanded shining black spots ol' 

 the abdomen, which coalesce wholly or partly. The 

 figure shows the extreme of coalescence, but even the 

 minimum that I have seen looks very different from 

 the western form. One male has the fourth abdominal 

 segment and hypopygium mostly red. The number 

 of ps dc evidently varies from three to four, but the 

 fourth (just behind the suture) is small if present. 

 The front measures in the males .333, .350, and .353 

 of the head (average .345, slightly more than in mei- 

 genii), and in the females .417 and .424 (average 

 .420). 



Three males and two females : two males and one 

 female are from Ludlo\^^^ille, Xew York, in the Car- 

 negie Museum; one male and one female Rochester 

 Junction, N. Y., collected by ]M. D. Leonard. 



Type. — Male, in British INIuseum. 



Vigil antedates meigenii by thirteen years (1849, 

 1862), and would replace the latter if it were ever 

 shown that they are one species. The distinct geo- 

 graphical boundaries, and the apparent absence of the 

 vigil form in Europe, added to the obvious color char- 

 acters, seem to assure the distinctness of the species. 



Genus JOHNSONIA Coq. 



Coquillett, Proc. Acad. Nat. Sciences Phil , 1895, 316, fe- 

 male. 

 Head rather rounded, front broad in both sexes, 

 with one proclinate orbital bristle in each; frontals 

 only four or five, strong and somewhat reclinate, the 

 rows not diverging below and reaching hardly to the 

 base of the antenuct; ocellars minute; frontal stripe 

 narrow, especially anteriorly; antenna of ordinary 

 size, third joint about twice the second, arista as usual 

 in Sarcophaga, long-plumose for more than half its 

 length; bucca narrow, a long turned-down bristle di- 

 rectly below the eye near its lower edge; palpi nor- 

 mal, proboscis short, eyes bare. 



