Assistance with field work is acknowledged from the Kansas University Endowment Association and the National Science Foundation. The figures were drawn by Victor Hogg. Bacula were prepared for study following the method outlined by White (Jour. Mamm., 32:125, February 15, 1951). _Specimens examined._--Total, 15, all in the Museum of Natural History at the University of Kansas. Localities within any one state are arranged from north to south. _Chihuahua_: Sierra Almagre, 6000 ft., 12 mi. S Jaco, 1. _Coahuila_: 17 mi. N and 8 mi. W Saltillo, 5200 ft., 2; 3 mi. SE Torreon, 3800 ft., 7. _Durango_: 1 mi. SSE Mapimi, 4100 ft., 1; 4 mi. WSW Lerdo, 3800 ft., 1; 5 mi. SE Lerdo, 3800 ft., 1. _Zacatecas_: Conception del Oro, 7680 ft., 1. _San Luis Potosi_: 10 mi. NE San Luis Potosi, 6000 ft., 1. _Other records._--_Coahuila_: Jaral; Saltillo (Goldman, 1910:82). _San Luis Potosi_: Cerro Penon Blanco; Ventura; Santa Teresa; city of San Luis Potosi (Dalquest, _loc. cit._). _Transmitted February 8, 1955._ 25-7820