OF THE TABANID^ OF THE UNITED STATES. 395 



3. Chrysops quadrivittatus Say, J. Acad. Phil., iii, 33, 1 (1822) ; Wied., Auss. Zwcifl., i, p. 200, 9. 

 Rocky Mts. 



4. Chrysops sepulchralis Kirby, Fauna Bor. Amer., p. 314, 1. 



Whether it is really identical with Fabricius's species of that name, remains to be proved ; 

 this identification certainly shows that the species belongs to the group provided with an 

 apical spot. 



SILVIUS. 



The only North American species of this genus hitherto described, S. isabeUhius Wied., 

 I have never seen. The following species is a true Sllvius from the Pacific basin ; it differs, 

 however, from the European species in the presence, on the face, of shining black callosi- 

 ties. 



Silvius trifolium n. sp. 



$ . Thorax clothed with a dense yellowish pollen, abdomen reddish-yellow, at the base with three elon- 

 gated blackish spots, connected at their ends in the sliaj)e of a clover-leaf. 

 Length 11.5 mm.; wing 10.5 mm. 



Head grayish-yellow, from a dense pollen which covers it ; small areas round the ocelli, 

 an obcordiform frontal callosity and two regular spots on the fixce, below the antennaa, shin- 

 ing black. Antennae : two basal joints and base of the third, reddish-yellow, the remainder 

 black ; palpi reddish-yellow. Thorax : ground color black, but altogether concealed under 

 a thick grayish-yellow pollen ; plourte with yellow hairs. Abdomen reddish-yellow, some- 

 what purer yellow on the posterior margins of the last segments, clothed with some ap- 

 pressed minute l^lack hairs ; the posterior margins of the segments show traces of a frino-e of 

 yellow hairs; the first segment has a blackish spot in the shape of a recumbent, elono-ated 

 8, both lobes of which are situated on both sides of the scutellum ; on the second seo-ment, 

 in the middle, there is an elongated spot of the same color, which, with the spots of the 

 first segment, forms a figure not unlike a clover-leaf; these spots are clothed with yellow- 

 ish pollen. Ventsr reddish-yellow, with a trapezoidal black spot at the base. Feet reddish- 

 yellow ; knees, tibiai and tarsal joints tipped with brown : tarsi altogether brownish towards 

 the end ; hind tibia? beset with black hairs. Wings hyaline with a grayish tinge ; the base 

 the costal areas and stigma tinged with yellow ; the fork of the third vein has a stump of a 

 vein. 



Vancouver Island (G. R. Crotch) ; Washington Territory. Two female specimens. 



HiEMATOPOTA. 



Bssides H. pimctulata Macq., Dipt. Exot., i, 1, p. 163, from the Carolinas, Avhich I do not 

 know, the following species occurs in North America, and seems to be very common in the 

 Northwest. 



Hgematopota amsricana n. sp. 



Fem-de. Grayish-black, variegated with white lines and spots; wings grayish, with numerous irre<rnlar 

 whitJ streaks and a hirge ocellar spot, having the base of the second posterior cell for its centre. Antennre 

 black, first johit very much incrassated, the third somawhat pale at the extreme base only; a large, shinin"-, 

 black, transverse callosity above them; two velvety black spots above the callosity. Feet black; front tibiai 



