1904.] Allen, Mammals from Northwestern Durango. 209 



anal region deep orange rufous; head stripes and ears as in dorsalis 

 but the dark stripes are stronger, the white stripes clearer white, and 

 the post-auricular white patch larger and more conspicuous. 



Measurements. Type: Total length, 254 mm.; head and body, 140; 

 tail vertebrae, 114; hind foot, 35; ear from crown, 1 6 ; ear from notch, 

 19.5. Skull, total length, 38; zygomatic breadth, 20. Three other 

 specimens have practically the same measurements as the type, and 

 two others (young adults) are somewhat smaller. 



Based on 9 specimens, all collected at Guanacevi, Oct. 817. 



Eutamias canescens belongs distinctly to the E. dorsalis 

 group, but differs from true dorsalis in the greater distinctness 

 of the dorsal stripes and the deeper fulvous of the sides. Two 

 specimens from Colonia Garcia, Chihuahua, collected Oct. 12, 

 and thus strictly comparable as to season, closely agree with 

 the Durango series. This is apparently the first record of the 

 E. dorsalis group in Mexico. Two very distinct species of 

 Eutamias durangcz and canescens thus occur in the 

 mountain ranges of northwestern Durango. 



5. Citellus grammurus rupestris Allen. Nine specimens, 6 

 adult and 3 young, Guanacevi, Oct. 8-17. Two of the adults 

 are still partly in the discolored, greatly worn pelage of 

 summer; the other four adults have moulted into fall pelage. 

 The young are less than one quarter grown, showing that 

 the young are sometimes born as late as the latter part of 

 September. As the April and May series contained no young, 

 and no females that were nursing young when killed, the 

 breeding season does not begin apparently till June and con- 

 tinues till late in September. 



* 6. Citellus spilosoma (Bennett). Three specimens, an 

 adult female and two young in first pelage, Rio Ocampo, 

 June 30. 



7. Mus alexandrinus Geoff roy. Two specimens, San Andres, 

 Oct. 15. 



8. Mus musculus Linn. Two specimens, Guanacevi, Oct. 

 19. 



