162 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



times for ueaily half their length, light yellow ; middle, sometimes all 

 the metatarsi, yellowish ; the I'emora, except the tip, black; distal por- 

 tion of tibiae blackish brown. Wings hyaline. 

 Numerous specimens. 



Eristalis hirtus. 



Eristahs hirtiis Loew, Ceutnr., vi, 66; Osten Sackeu, West. Dipt., 335; Willis- 



tou, Proc. Am. Phil. Soc, 1882, 319. 

 Eristalis temporalis Thomson, Dipt. Eug. Eesa, 490, 77. 



Habitat. — Washington, Oregon, California, Colorado, Western Kan- 

 sas ! 



5,5. Length, 10 to 15""". Face black, more or less concealed be- 

 neath a sometimes dense grayish or reddish pollen, the pile whitish. A 

 narrow strii)e in the middle and the cheeks bare, vshining. Below the 

 antennal process the face is nearly vertical to the tip of the tubercle. 

 Frontal triangle convex, with obscure yellowish pile. Eyes in the male 

 broadly contiguous ; in the female the front is convex and very broad, 

 the sides converging but very slightly on the upper half; thickly yel- 

 lowish pollinose, less dense in the middle and upper part, so that the 

 shining ground color appears ; thickly clothed with yellowish pile. An- 

 tennae black ; arista reddish, briefly pilose near the base. Thorax 

 black, shining, rather thickly clothed with the same obscure yellowish 

 pile. Scutellum sub- translucent yellow, black at the base. Abdomen 

 black ; the sides of the second segment with a large triangular spot, 

 usually yellowish, sometimes quite yellow, in others only metallic ; the 

 segment elsewhere opaque ; third segment with an opaque black ftiscia 

 behind, not interrupted, and a small triangular spot in front; remain- 

 der of the third, and the following segments, shining black, except that 

 the fourth segment usually has a very small triangular opaque spot in 

 front ; pile short, obscure yellowish, black on the opaque portions ; 

 second, third, and fourth segments usually margined behind with light 

 yellow, in some specimens almost wholly wanting. Legs black; tip of 

 femora and base of tibiaj, the middle tibiae almost wholly, and the first 

 two joints of the middle tarsi, yellow. Wings hyaline; in some speci- 

 mens with a -large faint brownish spot in the middle of the wing. 

 Thirty specimens. 



This species varies much in the yellow coloration of the abdomen. 

 According to Osten Sacken, the specimens with obsolete and sub-obso- 

 lete yellow spots on the sides of the second segment seem to come from 

 higher altitudes. 



Uristalis dimidiatus. 



Eristalis dimidiatus 'Wiedemann, Auss. Zw. Ins., ii, 180, 41. 



Eristalis inflexus Walker, List., etc., iii, 617. 



Eristalis niger Macquart, Hist. Nat. Dipt., i, 505, 15. 



Eristalis UHerminierii Macquart, Dipt. Exot., ii, 2, 55, 38 (male). 



Eristalis chalijbeiis Macquart, Dii)t. Exot., ii, 2, 55, 39 (female). 



Eristalis incisuralis Macquart, Dipt. Exot., 4e Suppl., 139, 64 (male). 



Habitat. — Atlantic States, Kansas ! 



