336 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



temporalis Thomson, Eug. TCesa, 490.) — Common in California as well 

 as in the Koeky Mountains (environs of San Francisco, May, June ; 

 Yosemite, June; Lake Tahoe, July 19 ; Webber Lake, July 27 ; George- 

 town, Colo., August 12). I have also specimens from South Park and 

 Twin Lakes, Colorado, by W. L. Carpenter. 



The specimens vary in size from 5 mm to 8 mm . As a rule, those from high 

 altitudes are smaller and darker in color. To Mr. Loew's description of 

 the male, otherwise remarkably accurate and complete, should be added 

 that the frontal triangle above the antennas is rather convex, and bears 

 a conspicuous tuft of yellowish pile; on the anterior part of the fourth 

 abdominal segment, in the middle, there is a velvet-black streak, similar 

 to a corresponding streak on the preceding segment; and, instead of 

 "in segmentorum tertii et quarti partibus nigrovelutinis", read "sec Midi 

 et tertii". 



The female has a remarkably broad and convex front, a very charac- 

 teristic mark of the species ; it bears a dense crop of yellowish hair. 

 The black vertex has some black pile in the middle. The yellow triangles 

 on the second abdominal segment are usually smaller than in the male; 

 in many specimens, they are subobsolete, brownish ; often the yellow 

 disappears entirely, leaving only two shining black triangles on velvety- 

 black ground. On the wings, there is, in some specimens, a brownish 

 shadow in the middle, immediately beyond the central cross-veins. The 

 specimens with the obsolete and subobsolete yellow abdominal triangles 

 seem to come principally from the higher altitudes. 



I have seven males and twenty females. 



Eristalis stipator n. sp. — Eyes pubescent, the yellow arista bare ; 

 second abdominal segment with a yellow triangle on each side, framed 

 in posteriorly by a velvety-black cross-band, interrupted (or subinter- 

 rupted) in the middle ; narrow posterior margins of segments 2-4 yellow- 

 ish-white, beset with a rather conspicuous fringe of pale golden -yellow, 

 comparatively long hairs, this fringe being broadest on the fourth seg- 

 ment. Length 9 mm to 13 mm , sometimes larger. 



Male. — Face yellowish-white, densely clothed with hairs of the same 

 color; the black stripe in the middle is rather broad; cheeks black, 

 shining; antennas black, third joint dark brown ; arista reddish-yellow, 

 glabrous ; eyes pubescent, the suture between them rather short (about 

 half as long as the interval between apex of the frontal triangle and the 

 root of the antennas), the apex of the vertical triangle being considera- 

 bly prolonged in front of the antennas. Thorax greenish-black, uuicol- 

 orous, shining, beset with yellowish pile, w 7 hichis denser on the pleuras. 

 Scutellum reddish-brown. Second abdominal segment with a yellow tri- 

 angle of the usual shape on each side ; a velvet-black cross-band on the 

 anterior margin, another one along the posterior side of the yellow 

 triangles; the latter is interrupted (or subinterrupted) in the middle, 

 oblique on each side, and interrupted before reaching the lateral margin ; 

 a smooth bluish- black space is inclosed between the two cross bands 





