SNOW: DIPTERA OF COLORADO AND NEW MEXICO. 235 



inner end; spots of fourth segment similar but generally joined together 

 and always resting broadly upon the anterior margin; fourth and fifth 

 segments more shining than the preceding with narrow yellow or light 

 green hind borders. Halteres with a greenish yellow knob. Legs 

 yellow, with the distal half of the anterior femora, nearly the whole of 

 the hind femora, a more or less broad ring on the hind tibiae and the 

 hind tarsi except the basal joint, black; anterior tarsi brownish. Wings 

 hyaline or slightly brownish; stigma brown. 



Female. Front gradually narrowed from antennae to ocelli where 

 it is distinctly narrower than half the length of the front, shining 

 black, across the middle with a broad uninterrupted arcuate band of 

 yellow pollen; fifth segment of abdomen with a yellowish spot in 

 the anterior angles. 



Thirteen males, top of Deer mountain, Estes Park, Colo. (Aug); 

 seven males and two females, Hop Canyon, Magdalena mountains, 

 N. M., (Aug., 7500 to 9500 ft.). 



This species differs from the description of pai/xiiliis Will. (Sy- 

 nopsis, p. 74) in the color of the face, cheeks and thorax; the abdo- 

 men is obsoletely shining except on the last segment; the lunate spots 

 of the abdomen are not of equal width; the distance from ocelli to 

 antennae is not distinctly less than that from antennae to the tip of the 

 tubercle. The two species must however bear a marked resemblance 

 to each other. 



Syrphus ribesii Linn. 



Five specimens, Manitou Park, Colo. (Aug.); twenty specimens. 

 Hop Canyon, Magdalena mountains, N. M. (Aug., 8000 ft.). In the 

 latter locality the species became rather common only towarfl the 

 end of August, and at a considerable altitude. A female from Col- 

 orado (Gillette, No. 1752) is remarkable in that the abdominal bands 

 are all distinctly interrupted. — Common to Europe and South 

 America. 



Syrphus sp. 



Related to torvtis. Eyes pilose; cheeks yellow; scutellum yellow; 

 the abdominal spots reach the lateral margins broadly. 



Female. Differs from torvus as follows: Face with a short black 

 stripe on the tubercle; the blackish brown arch above the antennae 

 has no projecting angle in the middle; antenna; uniformly black; 

 thorax with considerable luster; the yellow spots on the second ab- 

 dominal segment reach the lateral margin in nearly their full width 

 and are not prolonged in a neck; yellow crossbands of the third and 

 fourth segments are strongly biconvex on their hind margins, with a 

 deep sinus in the middle; they are scarcely attenuated on the sides, 



