_Reithrodontomys chrysopsis seclusus_ Hall and Villa, Proc.
Biol. Soc. Washington, 62: 163, August 23, 1949, type from
Mount TancA-taro, 7,800 ft., MichoacAin.
_Reithrodontomys chrysopsis chrysopsis_, Howell, N. Amer.
Fauna, 36:66, June 5, 1914, part.
_Range._--Known only from Mount TancA-taro, from 6,000 feet elevation
up to at least 11,000 feet.
_Specimens examined_, 22: nos. 51407-51411, 52110-52126, all from
Mount TancA-taro, distributed by altitude as follows: 6,000 ft., 5;
7,800 ft., 10; 10,500 ft., 1; 11,000 ft., 1; no altitude recorded, 5.
_Remarks._--The 22 specimens in the Chicago Natural History Museum are
remarkably uniform in color in spite of differences in age; 17 are so
young as to have the first upper molar only slightly worn and 5 are
adults. In preparing the original description of _R. c. seclusus_,
known only from specimens in the summer pelage, comparison of color
was made with only the winter pelage of _R. c. chrysopsis_ and it was
pointed out that the differences noted in color between the two
subspecies might be seasonal rather than subspecific. A summer
specimen of _R. c. chrysopsis_ (K. U. 17980, taken on June 15, 12 km.
ESE Amecameca, 11,500 ft.), is available as the present account is
being written. In direct comparison with the original material of _R.
c. seclusus_, all in summer pelage, and in comparison with a specimen
of _R. c. chrysopsis_ in winter pelage (January 18), from 30 km. E
Amecameca, the summer pelage of no. 17980 is more blackish than the
winter pelage and therein more closely resembles that of _R. c.
seclusus_. The same is true of the more sparsely haired tail. The
ears, however, are blackish as in winter-taken _R. c. chrysopsis_.
This feature and also the large size and different cranial proportions
of specimen no. 17980 are in accordance with the differences between
_R. c. chrysopsis_ and _R. c. seclusus_ as recorded in the original
description of the latter.
=Baiomys taylori analogus= (Osgood)