194 PROCEEDINGS OF THE ACADEMY OF [1898. 



A NEW GRASSHOPPER MOUSE FROM NEW MEXICO. 

 BY SAMUEL N. RHOADS. 



Among the ten species and races of short-tailed mice of the genus 

 Onychomys known to inhabit the United States we find a surpris- 

 ingly small amount of color variation, or of difference in size and 

 external proportions, from the type of the genus, 0. leucog aster, from 

 Dakota. The short, nearly unicolor, blunt tail, rounded, microtine 

 ears, dense, silky pelage and buff)'- gray colors are more or less char- 

 acteristic of all the species ranging from the Saskatchewan to the 

 Mexican boundary. 



A careful study of their cranial characters is thus necessary in 

 determining their relationships. 



A specimen of Onychomys in superficial appearance almost identi- 

 cal with leucogaster, was recently forwarded to the writer from Me- 

 silla, Dona Ana Co., New Mexico, by Mr. T. D. A. Cockerel!, for 

 identification. Four specimens of Onychomys from Clapham, Union 

 Co., New Mexico, prove to be identical with the Mesilla specimen 

 and on comparison with their nearest geographical allies, leucogas- 

 ter, brevicaudus and longipes prove to belong to a distinct and un- 

 described species. It may be known by the following diagnosis : — 



Onychomys arcticeps sp. nov. Long-Nosed Grasshopper Mouse. 



"Onychomys leucogaster subsp.?"; Allen, Bull. Araer. Mus. N. H., 1893, 

 p. 74. ''Onychomys leucogaster brevicauda" ; Allen, ibid, 1896, p. 253. 



Type No. 1,529, ad. $ , col. of S. N. Rhoads, taken by E. E. 

 Thompson at Clapham, Union Co., New Mexico, Nov. 7th, 1893. 



General characters. — About the size of leucogaster, with slightly 

 longer tail and ears, deeper fulvous (less gray) coloration above, 

 narrower cranium, and long, slender rostrum. 



Color. — Above uniform ochraceous buff, 1 heavily lined with black- 

 ish, lightest along sides, blackest on top of head and around eyes. 

 A blackish oval spot on upper, outer margins of ears. Tail white, 

 with an ill-defined, narrow stripe of blackish-buff on superior prox- 

 imal two-thirds. Color of sides at the white margin and on lower 

 rump and thighs deeper ochraceous buff. Lower parts tawny white 

 as contrasted with the clear, pure white of leucogaster. 



1 Ridgway's Nomen. of Colors, PI. V, No. 10. 



