Some of the Pleistocene mammals from San Josecito Cave, near Aramberri, Nuevo León, México, collected by field parties of the California Institute of Technology under the direction of the late Professor Chester Stock, have been reported previously (see Furlong, 1943; Cushing, 1945; Stock, 1950; Hooper, 1952; Findley, 1953; Stock, 1953; Handley, 1955; Jackway, 1958). In 1950, Professor Stock loaned a portion of the San Josecito material to the University of Kansas for identification. Included therein were 89 crania and rami of bats, representing three families (Phyllostomidae, Desmodontidae and Vespertilionidae) and five genera, each represented by a single species. One of the species is here described as new. Three of the kinds are known only from the Pleistocene and two are Recent species.