82 KANSAS UNIVERSITY SCIENCE BULLETIN. 



bluish-white dust ; halteres and tegulse yellow ; cilia of the 

 latter black. Abdomen with a ringed appearance, the ante- 

 rior half of each segment bright green, on the sides whitish- 

 dusted, the posterior half blackish, dull ; hypopygium large, 

 whitish-dusted ; the lamellae very small, yellow, with the ap- 

 ical third blackish. Front coxae and the tips of the others yel- 

 low ; femora and tibiae yellow, fore tarsi infuscated at the tip 

 only, middle ones from the tip of the first joint, hind ones from 

 the base ; hind femora and tibiae both distinctly darkened at 

 the apex. Wings with a yellowish tinge, the fourth vein bent 

 forward near its tip and thence nearly straight, as in Pelastg- 

 neurus. The hind femora have a row of bristles above of 

 which the last four or live toward the end are quite conspicu- 

 ous. 



Length, 3.1 to 3.6 mm. Four males, seven females. 



PELASTONEURUS. 



Loew, Neue Beitr., VIII, 36, 1861 ; Monogr., 103. 



Pelastoneurus argentiferus. 



Aldrich, Trans. Lond. Entom. Soc, 1896, 313. 



Thirty-five specimens, both sexes. 



SARCIONUS. 



Aldrich, Biologia, Dipt., Suppl., 1902. 



Sarcionus lineatus. 



Aldrich, Trans. Lond. Entom. Soc, 1896, 312 {Pelastoneurus). 



Numerous specimens, both sexes. The width of the face in 

 the male is one-twelfth, in the female one-sixth, the width of 

 the head ; therefore the species cannot be a Pelastoneurus. 



HERCOSTOMUS. 



Loew, Neue Beitr., V, 9, 1857. 



Hercostomus latipes. 



Aldrich, Trans. Lond. Entom. Soc, 1896, 311. 



Numerous specimens, both sexes. 



NEURIGONA. 



Rondani, Prod. Dipt. Ital., 142, 1856. 



Neurigona signifera. 



Aldrich, Trans. Lond. Entom. Soc, 1896, 337. 



One male. 



