MAMMALS OF THE MEXICAN BOUNDARY. 341 



more rapid. As pointed out by Dr. J. A. Allen," in the case of the red 

 squirrel {Saiurun Imdmnluiui) and chipmunks (genus Entamias), the 

 sequence of the autumnal change of pelage is just the reverse of what 

 occurs during the vernal molt, the tail being the first part to receive 

 the winter coating and the head and feet the last. Lactation appears 

 to exert some influence in retarding the molt, but this is less marked 

 in the South than the North, where parturition bears a more definite 

 relation to season and temperature. 



Specimeni? taken at El Paso, Texas, February 7, were in complete 

 winter pelage. The species was next met with at Dog Spring, Grant 

 County, New Mexico, where nine specimens, taken during the last 

 week of May, were in mixed winter and summer pekge. The males 

 and virgin females had, with one exception, received the summer 

 pelage except on the tail. Nursing females were in summer pelage 

 anteriorly, and posteriorly the overhair had fallen out, leaving the 

 underfur exposed. Six specimens, from the Animas Valley, which 

 has a considerably higher altitude than Dog Springs, taken June 29, 

 are no further advanced than the Dog Springs series, killed a month 

 earlier, none of the males having completed the summer molt. Not 

 one of eleven specimens taken during the last week of July, on 

 the San Pedro River at Monument No. 98, had received the whole 

 summer coat, although several were almost in summer pelage. Of 

 four females, taken June 19, at Belen, Texas, the lowest point at 

 which the species was collected, three are entirely in summer pelage 

 and the fourth nearly so. A female, taken July 5 in the Animas 

 Valley near Monument No. 66, had not quite completed the summer 

 pelage; but two males, from Cloverdale, on the opposite side of the 

 same valley, taken July 15, were in perfect summer dress. 



Eight specimens from the Animas Valley, taken by the writer, 

 August 31 to October 3, 1893, show the whole progress of the 

 autumnal molt very satisfactorily. Specimen No. 58915, U.S.N.M., 

 has molted the summer hair on the tail, which is coated with winter 

 hair. The body still i-etains the summer hair, but on parting this 

 short, scant coat, the new winter hair, copiously mixed with underfur, 

 may be seen sprouting. The other two specimens of the same date are 

 somewhat further advanced. In four September specimens, the winter 

 coat has extended forward as far as the head above, and is appearing 

 on the under surface of the body. Specimen No. 58921, U.S.N.M., 

 taken October 2, is in perfect winter coat, and the black bar on the 

 tail — the first part to acquire the winter coat — is already fading to 

 brownish. Eleven specimens from the San Pedro Valley, taken Octo- 

 ber 14 and 21, are all in winter pelage, except a small area on the front 

 of the head in several specimens. 



a Bull. Am. Mus. Nat. Hist., Ill, 1890, pp. 41-116. 



