242 KANSAS UNIVERSITY QUARTERLY. 



April i8, May 23); Magdalena mountains, N. M. (Aug., 9,000 ft.) 

 From the latter locality are thirty males and twenty-eight females 

 taken along with certain species of Volucella. The females are all 

 light colored and show the yellow thoracic markings distinctly, while 

 the males without exception belong to Williston's dark variety lentum. 

 This would indicate that the differences between these forms are 

 sexual rather than varietal, since both were taken at the same time 

 and place. A western and southern species. 



Ssricomyia militaris Walk. 



Eight males and six females, Manitou Park, Colo. (July, Aug.); 

 four males and one female, Estes Park, Colo. (Aug.); one male, 

 ('olorado (Gillette, No. 788); one male. New Mexico (Gaumer). 

 Sericomyia is a northern genus and specimens from localities to the 

 south of Colorado are rare. 

 Arctophila flagrans O. S. 



Eighteen males and four females, Manitou Park, Colo. (July, Aug., 

 on the tops of mountains); fifteen males, Estes Park, Colo. (Aug., at 

 high altitudes); one female, Colorado (Gillette No. 788); four males, 

 Magdalena mountains, N. M. (Aug., on top of "Big Baldy " moun- 

 tain, 10,000 ft.); twenty males. New Mexico (Gaumer). So 

 far as I know this species is taken only on the summits of mountains 

 of considerable height. 

 Eristalis tenax Linn. 



Manitou Park, Colo. (July); Estes Park, Colo. (Aug.). Common all 

 over the world. 

 Eristalis hirtus Lnew . 



Over one hundred specimens, Bailey, Colo. (Aug.); Manitou Park, 

 Colo. (July, Aug.); Estes Park, Colo. (Aug.); Manitou, Colo. (Aug.); 

 Colorado (F. H. Snow; Gillette, No. 823); five specimens, Magda- 

 lena, mountains, N. M. (/Vug.). This species is seemingly much 

 more common in Colorado than in New Mexico. It is distinctly 

 western. 

 Eristalis latifrons Loew. 



More than two hundred specimens, Bailey, Colo. (Aug.); Manitou 

 Park, Colo. (July, Aug.); Estes Park, Colo. (Aug.); Colorado Springs 

 (Aug.); Colorado (F. H. Snow; Gillette, No. 1722); New Mexico 

 (F. H. Snow; Gaumer); Las Cruces, N. M. (Townsend April 8, 9; 

 June 7-28); Albuquerque, N. M. (Aug.); Magdalena mountains, N. 

 M. (Aug.). In the latter locality this species ranged up to 10,000 feet 

 and was most numerous at about 9,000, in company with several 

 species of Syrphus, Volucella and Copestylutn. Another western 

 species. 



