328 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



narrow (not much broader than one-fourth of the breadth of the segment), 

 attenuated in the middle (even subinterrupted in one of the specimens) ; 

 their ends are separated from the lateral margin by a narrow black 

 interval ; posterior margin of the fourth segment with a narrow red- 

 dish border; that of the fifth still narrower. Legs reddish-yellow; 

 proximal half (or nearly so) of the four anterior femora black; hind 

 femora black, except at tip ; hind tarsi infuscated. Stigma brownish ; 

 both costal cells distinctly tinged with brown. Length 9-ll mm . 



Female. — I have two specimens which I refer to this species, on ac- 

 count of their entirely yellow face and the course of the cross-bauds, 

 which is nearly the same as in the male; but the femora are entirely 

 reddish-yellow, coxae and trochanters remaining black. Vertex green- 

 ish-black ; front metallic-green, densely yellowish- pollinose, its lower 

 part reddish-yellow, except two brownish marks above the root of the 

 antennae. 



Hob. — Marin County, California (Saucelito, April 2 ; San Geronimo, 

 April 20). Two males and two females. 



6. Syephus peoteitus n. sp. — Male. — Eyes glabrous; face yellow, 

 with a bluish opalescence ; on the cheeks a large blackish spot below the 

 eye, and not quite reaching the oral margin (it is variable in size, some- 

 times very small) ; the lower edge of the head behind the mouth and be- 

 tween the lower end of the eyes is again yellow. Autennae red, some- 

 times faintly brown on the upper side of the third joint; front brownish- 

 yellow above the antennae, black, slightly pruinose, and with black pile in 

 the corner between the eyes ; vertex black, with black pile ; occiput gray- 

 ish, beset with pale hairs. Thorax dark bronze-green, beset with dense 

 yellowish pile. Scutellum yellowish, with black pile, some yellowish 

 hairs on each side. Abdomen black, opaque, with three reddish-yellow 

 cross-bands, the first of which is broadly interrupted ; the two yellow 

 spots thus formed are prolonged along the lateral margin to the very base 

 of the abdomen ; the second and third bands reach the lateral margin, 

 being only a little attenuated before it; they are biconvex posteriorly, 

 with an angular emargination in the middle; fourth segment with a yel- 

 low border posteriorly ; the fifth red, with a black triangle in the middle. 

 Legs altogether reddish, often a brown shade in the middle of the hind 

 tibiae and on the hind tarsi ; femora red from the very base ; coxae and 

 trochanters black. Wings subhyaline ; their root tinged with brownish, 

 the costal cell with yellowish ; stigma brownish-yellow ; third vein nearly 

 straight. Length 10-12 mm . 



Jffab. — Saucelito, Marin County, Cal., April. Four males. 



Is very like the common S. rectus of the Atlantic States; only in that 

 species the male has black hind femora, the black spot on the cheeks is 

 smaller, and the antennae are much darker. 



Eupeodes nov. gen. 

 Very like Syrphus, from which it can be at once distinguished in the 

 male sex by the large development of the sixth abdominal segment and 



