Topotypes of _L. n. nivalis_ from Mount Orizaba were not available, but 111 specimens referable to the subspecies _nivalis_ were examined. These specimens were from the following places: _Sonora_: 1/4 mi. W Aduana, 1600 ft., 4 specimens. _Jalisco_: Hda. San Martin, 5000 ft., 18 mi. W Chapala, 3; 11 mi. W Chapala, 5000 ft., 1; 5 mi. W Chapala, 5000 ft., 58; 8 mi. NE Ocotlan, 5100 ft., 1. _Hidalgo_: 6 km. NW Tasquillo, 500 ft., 1. _Veracruz_: 3 km. W Boca del Rio, 25 ft., 22. _Distrito Federal_: Chicomostoc, Cerro Teutli, 2-2/5 mi. NNW Milpa Alta, 2620 ft., 18. _Oaxaca_: Cuicatlan, 600 ft., 1; 3 km. WNW Dominguillo, 730 ft., 2. All these specimens are in the Museum of Natural History at the University of Kansas. Little discernible geographic variation was found in these specimens of _L. n. nivalis_. No specimens could, with certainty, be classed as intergrades between _longala_ and _nivalis_, but it is thought that intergrades will be found in western San Luis Potosi or in Zacatecas or in both states. Dalquest (Mammals of the Mexican State of San Luis Potosi, Louisiana State Univ. Studies, Biol. Sci. Ser. No. 1, pp. 27-28, 1953) refers five specimens taken from Hda. Capulin, southeastern San Luis Potosi, to _L. n. nivalis_. Measurements by Dalquest are in accordance with other measurements of _L. n. nivalis_ listed above. The name _L. n. yerbabuenae_ Martinez and Villa, was based on specimens from Yerbabuena in the state of Guerrero. The specimens, including the holotype, on which this name was based have been destroyed. Luis de la Torre (Fieldiana, 37:698, 1955) examined a topotype of _yerbabuenae_ and was unable to distinguish this specimen from a topotype of _nivalis_ from Orizaba. Davis and Russell (Jour. Mamm., 33:236, 1952) identified as _L. n. nivalis_ one bat from Morelos, taken approximately 32 miles NE of the type locality of _yerbabuenae_, noting that its third finger was much shorter than in specimens from the Big Bend of Texas. I judge _L. n. yerbabuenae_ to be a synonym of _nivalis_ as does de la Torre. Acknowledgment is made to Dr. W. B. Davis of the Agricultural and Mechanical College of Texas and Mr. Colin C. Sanborn of the Chicago Natural History Museum for loan of comparative material. I am grateful also to the Kansas University Endowment Association and National Science Foundation for support of field work, and to Dr. Rollin H. Baker for guidance in my study.