UHLER ON INSECTS. 781 



Anthrax sinuosa Wied. 



Eather common in Clear Creek Caiiou and Beaver Brook Gulcli, 

 August G and 7, but not seen in any other locality. At Denver it was 

 replaced by another species, and at Colorado Springs and fartiier south 

 still other species occurred. 



Anthrax halcyon Say. 

 Not rare at Colorado Springs and Manitou, August 12 to IG. 



Anthrax allied to alternata Say. 



Rare in Clear Creek Caiiou, August G. A closely related, if not iden- 

 tical, species was common in the suburbs and vicinity of Denver, but 

 only one dwarf specimen reached home in good condition. 



Anthrax sp. 



Other species were found at Colorado Springs, and one or perhaps 

 two others were common on the highlands near and west of Denver. 



Thereva sp. 



Found in moderate abundance in the valley of the Arkansas near 

 Caiion City, August 10 and 11. 



Systcechus vulgaris Loew. 



Extremely common on the plains from Denver to Colorado Springs, 

 August 5 to 18; but no specimens occurred at Caiion City. It balances 

 itself above the flowers and plants in sunny spots, and flits from place 

 to place over short distances with such rapidity that the eye can 

 scarcely trace its flight. It is admirably protected by the yellow flowers 

 uijon which it sometimes alights. 



Lordotus (jihTjus Loew. 



This exquisite species was rare. One specimen was captured in the 

 act of settling on a sunflower at Colorado Springs, August 17, and 

 another at Denver, August 18. 



SimrnopoJius coloradensis Grote. 

 One specimen from near Colorado Springs, 



Phthiria siilphurea Loew. 

 Not uncommon in the vicinity of Colorado Springs. 



Fam. ASILID.E. 

 Asilus sp. 



A very large species is common on the low hills west of Denver, 

 August 8 to 18. It and two other kinds of somewhat smaller size were 

 seen seizing the different species of Calopteni, and destroying them. At 

 Colorado Springs, one of this group was very useful in killing Caloptenus 

 spretus, and, in the valley of the Arkansas, the same fact was observed 

 on several occasions. 



wSpecics of MaJIophora, Stenopogon, Scleropor/on, Machimus, Urax, and 

 Biogmites were found commonly on many parts of the plains and foot- 



