1917] New Species of Colorado Syrphidce 225 



stripe; scutellum light yellow with chiefly black pile; pleura with a 

 tuft of long yellow pile; halteres lemon yellow; abdomen black, opaque, 

 principally black pile, first segment entirely shining, lateral margins of 

 second, third and posterior portion of third and fourth shining. The 

 three pairs of yellow stripes reach the lateral margins. The first 

 pair, semi-ovate, attenuated laterally and rounded on inner angles; 

 second and third pairs semi-rectangular, inner margins rounded, sides 

 parallel, about two-thirds their length, thence slightly curv^ed anteriorly 

 and slightly attenuated, meeting the margins at the junction of pre- 

 ceding segment. Posterior margin of fourth and fifth segments bordered 

 with a yellow transverse line; legs slender, yellowish, with chiefly black 

 pile; bases of all femora black, all tibiae yellow, inner margins of meta- 

 tarsi of the front legs yellow, middle and hind metatarsi and tarsi 

 brownish black; wings hyaline, yellowish at base, sub-costal cell 

 brownish, darker at stigma. 



Habitat: One specimen, female, Estes Park, 7600 ft., 

 July 15, 1912, G. P. Weldon, Collector. 



S. similis differs from S. torvus in that the eyes are globose 

 and completely bare; and from ribesii, in that the femora are 

 black at the base, while in the 9 of ribesii they are yellow; and 

 in that the abdominal bands are almost straight and attenuated, 

 and that these spots show no convexity until they reach the 

 point where the attenuation begins; from the rounded inner 

 margins of the transverse bands up to the point of attenuation 

 the abdominal spots are almost quadrate. 



Sphaerophoria interrupta n. sp. 



Length, 9 , 8 mm. Front black, shining, with a black median 

 dash from the vertex, gradually becoming constricted in the middle to 

 a little more than one-half its width, thence gradually broadening to 

 its extreme width, and then tapering to a point above the antennae; 

 sides silvery pollinose, yellowish above the antennae, with black and 

 yellow pile; face pale yellow, with white pile and silvery pollen, except 

 on the tubercle; oral margin narrowly brownish; cheeks yellow, with a 

 dark brown spot; antennae brownish, third joint rounded; arista slightly 

 darker; occiput silvery pollinose, and with white pile; dorsum of thorax 

 metallic greenish black, shining, with a distinct slightly interrupted 

 spot at the base of the scutellum, the same shape and color of the 

 scutellum, but slightly smaller; the anti-sutural stripe broad, yellowish, 

 covered with whitish pollen, which gives it a bluish reflection; the post- 

 sutural, slightly narrowed, entirely yellow, and terminating in an acute 

 angle near the scutellum; pleurae black, with silver}' pollen and white 

 pile; scutellum yellow, translucent, with sparse whitish pile; abdomen 

 black, shining, with four yellow, interrupted cross-bands which reach 

 the lateral margins ; the first segment black ; with inconspicuous yellowish 

 side spots; second segment with two, semi-triangular, arcuate spots, 

 which reach the lateral margins near the anterior portion of the segment, 



