1916.] 



CYNOMYS LUDOVICIANUS AEIZONENSIS. 



19 



Wyoming: Arvada (Powder River Valley), 2; Camp Carling (=Fort Russell, near 

 Cheyenne), 2; Cheyenne, 6; Deer Creek, 1; Douglas, 4; Fort Fetterman, 2; 

 Ishawooa, 4; Newcastle, 4; Pine Bluff, 2; Pole Creek, 7; Sage Creek, 11.^ 



CYNOIMYS LUDOVICIANUS ARIZONENSIS Mearns. 



Arizona Prairie-Dog. 



(PI. I, figs. 2, 5; PI. II, fig. 2; PI. V, fig. 2.) 



1890. Cynomys arizonensis Meams, Bull. Amer. Mus. Nat. Hist., II, no. 4, p. 305, 

 February 21. 



1892. C[yno7nys] ludovicianus arizonensis Merriam, Proc. Biol. Soc. Washington, VII, 

 p. 158, July. 



Type locality. — Point of Mountain, near Willcox, Cochise County, 

 Arizona. 



Geographic distrihution. — Southeastern Arizona, southern and 

 central New Mexico, southwestern Texas, and adjacent portions of 

 Sonora and Chihuahua, Mexico. North to San Pedro and Santa 

 Rosa, New Mexico; east to the Pecos Valley; west to Huachuca, 

 Arizona; south to San Diego and Casas Grandes, Chihuahua, and to 

 Presidio County, Texas. 



Characters. — Like Cynomys ludovicianus ludovicianus but averaging 

 very slightly larger, and brighter colored; skull with larger audital 

 bullae, and with superior surface of maxillary root of zygoma bordering 

 premaxillary and frontal bones very broad, not deeply emarginate, 

 the zygoma as viewed from above not branching at sharp angle from 

 rostrum. 



Color. — Almost precisely as in the typical subspecies, but averaging 

 slightly brighter vinaceous-cinnamon in fresh summer pelage. 



There is a single wholly melanistic specimen from south of the 

 Guadalupe Mountains, in Texas, in the National Museum collection. 



Molt. — Specimens showing excessive molt are more common than 

 in the northern subspecies, and molting examples frequently exhibit 

 strange patterns of coloration. There are frequent mixtures of the 

 faded, left-over winter coat and the fresh reddish summer coat. 

 Excessive wear before any renewal sometimes leaves large parts of 

 the animal entirely black, the hair having been worn away com- 

 pletely except for the black underfur. Specimens in the much- worn 

 pelage of late summer, before any evidence of fall renewal, frequently 

 present a curious appearance: the color is pale ochraceous or yel- 

 lowish buff and the hairs appear brittle and dead, often matted and 

 twisted as if scorched by excessive heat. 



January and February skins are in the long, soft, faded winter 

 pelage. In the lower levels the spring molt occurs earlier than in the 

 more northern race, and the animals are usually in full fresh summer 

 coat, except for the tail, between the first part and middle of May. 

 The short, stiff, summer coat rapidly wears and is much changed 



1 Collection Amer. Mus. Nat. Hist. 



