Vol. XXVI, pp. 125-128 May 21, 1913 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



NOTES ON THE PIKAS OF COLORADO. 

 BY JUNIUS HENDERSON AND T. D. A. COCKERELL. 



Ochotona saxatilis Bangs was originally described from 

 Montgomery, near Mt. Lincoln, Park Comity, Colorado. So 

 far as we arc aware it has not Keen found outside of Colorado. 

 Until recently all the pikas of that State were supposed to belong 



to this form. A year ago Dr. Allen described Ochotona figginsi 

 from Pagoda Peak, Routt County, Colorado.* The type local- 

 ities of these two forms are only about 90 miles apart, hut are 

 separated by a broad zone of territory entirely unsuited to pikas, 

 which in the southern Rockies are seldom found below 9000 

 feel and are not usually abundant below 10,000. The saxatilis 

 locality is connected with the Front Range and with the Sangre 

 de Cristo Range by almost continuous altitudes of 9000 feet or 

 over. Hence saxatilis should he expected all along the crests of 

 the eastern mountains practically from the northern to the 

 southern boundary of the State. On the other hand, thefigginsi 

 locality is in an isolated mountain area, separated on all sides 

 from other high mountains by territory unfavorable to this 

 genus, so one should expect a distinct race to develop there. 

 The San Juan region to the southwest also forms a rather dis- 

 tinct mountain mass, hut it is really connected with the eastern 

 ranges by territory more or less favorable to pikas, so that it is 

 not so likely that the San Juan pikas would be distinct, though 

 by no means unlikely. The form which occurs in the range 

 west of North Park may also prove to be distinct, though not 

 as thoroughly isolated as the Pagoda Peak region. All of these 

 topographic features will clearly appear to the reader unfamiliar, 

 with the region, upon consulting the new topographic map of 



* Hull. Amer. Mus. Nat. Hist.. XXXI. 103- I'M. Mas 28, 1912. 



31— Paoc. Biol. Soc. Wash., Vol. XXVI. 1913. (125) 



