18 Everett E. Wehr 



Melanostoma concinnum Snow. Kans. Univ. Quart., iii, 229 (1895). 



One s taken at Monroe Canyon, Sioux County, on August 

 9, 1908 (L, Bruner). Prior to this the species had been re- 

 corded only from New Mexico and Colorado. 



Platychirus St. Fargeau and Serville 



KEY TO THE SPECIES 



1. Front tibiae of the male, on the inner side toward the end, 

 somewhat concave, the outer angle produced into a lappet-like 

 process, yellow spots on abdomen in both sexes very large, leav- 

 ing only a median stripe and cross-bands; hind femora and 

 tibiae yellow quadrat us 



Front tibiae of the male gently and evenly convex on the inner 

 side, the top on the outer side less produced, more angular; spots 

 of abdomen smaller; hind legs chiefly black 2 



2. Front femora in the male with a row of five to seven long 

 bristly hairs; second abdominal segment with large, the fifth 

 with small, yellow spots chaetopodus 



Front femora without such bristles; second segment of the 

 abdomen in both sexes with a small rounded spot on each side, 

 fifth segment in the male without yellow hyperboreiis 



Platychirus quadratus (Say.) Jr. Acad. Nat. Sci. Phil., iii, 90 (1823); 

 Osten Sacken, Cat. Dipt., 122 (1858). 



This species has a wide distribution in the state. Thirty- 

 one s S and thirty-four $ $ have been collected from the fol- 

 lowing localities: Glen, Sioux County; Mitchell, Scottsbluff 

 County; Neligh, Antelope County; Maskell, Dixon County; 

 Lincoln, Lancaster County, and Omaha, Douglas County, be- 

 tween May 9th and September 3rd. 



Platychirus chaetopodus Williston. Synop. N. A. Syrph., 59 (1886); 

 Snow, Kans. Univ. Quart., iii, 23 (1895). 



Five S $ and one 5 from Lincoln, Lancaster County, and 

 Sioux County. 



Platychirus hyperboreus. (Staeger.) Groenl. Antl., 362 (1845); Willis- 



124 



