=Lasiurus ega xanthinus= (Thomas) Southern Yellow Bat 1897. _Dasypterus ega xanthinus_ Thomas, Ann. Mag. Nat. Hist., ser. 6, 20:544, December, type from Sierra Laguna, Baja California. 1953. _Lasiurus ega xanthinus_, Dalquest, Louisiana State Univ. Studies, Biol. Ser., 1:61, December 28. _Distribution in Tamaulipas._--Probably occurs in southern and western parts of state; certainly known only from the Sierra de Tamaulipas. Three June-taken females, all captured in mist nets, were lactating. Hall and Jones (1961:91) assigned all Mexican specimens of the southern yellow bat to _Lasiurus ega xanthinus_, but remarked that specimens from western México were paler than those from the east. Of the six specimens examined from Tamaulipas, four are dark, resembling in color specimens from Veracruz, Yucatán and Costa Rica, and the other two are somewhat paler, approaching specimens from Baja California, Zacatecas and Coahuila. In measurements, Tamaulipan specimens of _Lasiurus ega_ generally resemble specimens from the west, but differ from any other _L. ega_ seen in having a longer tail, longer ear, and shorter maxillary tooth-row. _Records of occurrence._--Specimens examined, 6: Sierra de Tamaulipas, 10 mi. W, 2 mi. S Piedra, 1200 ft., 4; 10 mi. W, 3 mi. S. Piedra, 1200 ft., 1; 16 mi. W, 3 mi. S. Piedra, 1400 ft., 1. =Nycticeius humeralis= Evening Bat _Nycticeius humeralis_ has the same distributional pattern in Tamaulipas as has _Lasiurus borealis_ in that both are represented there by two subspecies, one known only from Matamoros and the other occurring in the rest of the state. Bats of this species (_N. h. mexicanus_) from Ciudad Victoria and some from the Sierra de Tamaulipas were shot in flight in evening; others from the last-mentioned locality were taken in mist nets. Lactating females (22 specimens) were collected in June and July. =Nycticeius humeralis humeralis= (Rafinesque) 1818. _Vespertilio humeralis_ Rafinesque, Amer. Monthly Mag., 3(6):445, October, type from Kentucky. 1819. _N[ycticeius]. humeralis_ Rafinesque, Jour. Phys. Chim. Hist. Nat. et Arts, Paris, 88:417, June. _Distribution in Tamaulipas._--Matamoros (Miller, 1897:120), one specimen. =Nycticeius humeralis mexicanus= Davis 1944. _Nycticeius humeralis mexicanus_ Davis, Jour. Mamm., 25:380, December 12, type from Río Ramos, 1000 ft., 20 km. NW Montemorelos, Nuevo León. _Distribution in Tamaulipas._--Known certainly only from central part, but probably occurs at suitable places in all but extreme northern Tamaulipas. Twenty-seven of 37 adults of _N. humeralis_ examined from Tamaulipas are pale as is _N. h. mexicanus_, but 10 are darker and approach _N. h. humeralis_ in this respect. Twenty-two females averaged 10.3 (9-13) grams and eight males averaged 9.5 (8-11) grams in weight.