782 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



hills, and less numerously in the caQons of the mountains. The species 

 and forms of this group must be very numerous in Colorado, and every 

 large locality seems to have one or more local forms. 



iStenopogon allied to trifasciatus Say occurs in numbers on damp sands 

 near the Arkansas Eiver, and also in Denver, near the South Platte 

 and its affluents. 



Osprioceriis ceacus Wied. 



This beautiful species, so strongly resembling a Midas, was found 

 near Colorado Springs and in the vicinity of CaQon City, August 11 to 16. 



Fam. DOLICHOPODID^. 



DolicJiopus sp. 



This vivid green insect was very common on the weeds of damp spots 

 in the suburbs of Denver. 



Fam. SYEPHID^. 



Eupeodes volucris O. S. 



A few specimens were taken by me at Denver and in Clear Creek 

 Caiion, but, to my surprise, it was not met with in any other locality 

 that I visited, August 6 to 8. 

 Eristalis stipator O. S. 



Found singly upon the white flowers of a low plant growing in the 

 meadow at Manitou Park, Colorado, August 14. 



Syritta pipiens Itima. 



Somewhat common at Denver and in Clear Creek Canon, August 6 

 to 18, and less common near Colorado Springs. 



Fam. TRYPETID^. 

 Trypeta sparsa Loew. 



Found in Manitou Park in very small numbers, August 14. 

 Trypeta alba Loew. 



Common near Caiion City, August 11. 

 Trypeta Jmmilis Loew. 



Moderately common at Denver, August 8 and later. 

 Trypeta {(Edicarena) persuasa O. S. 



Two specimens obtained by sweeping the weeds in the valley of the Ar- 

 kansas, near Caiion City, August 11. It has the same markings as seen 

 on the wings of a group of this genus belonging to Central America, 

 Cuba, Hayti, and Mexico, but is no doubt distinct from the species thus 

 far described. 



Trypeta sp. 



Allied to T. Solaris Loew. The specimens were taken in the vicinity 

 of Colorado Springs. 



