A New Species of Lizard (Genus

Throughout much of the range of the genus Cnemidophorus there are found sympatric pairs of apparently closely related species. Thus Cnemidophorus guttatus and C. deppei coexist in the tropical low-lands of both eastern and western Mexico. In southern Arizona and northern Sonora, Cnemidophorus stictogrammus and C. sacki exsan-guis are found together (Lowe, 1956). The Tepalcatepec Valley of Michoacin is inhabited by Cnemidophorus sacki and C. calidipes (Duellman, 1955). Farther south, in the basin of the Rio Balsas, Cnemidophorus gigas and C. s. sacki form a pair (Davis and Smith, 1952). In the vicinity of the city of Oaxaca the very large Cnemidophorus sacki australis is found together with C. sacki bocourti, a smaller form. ' Cnemidophorus s. australis also occurs in northern Oaxaca and adjacent Puebla and is paired with a smaller species that has escaped the critical attention of herpetologists. With reference to its position as the smaller member of a species pair, I name this form: Cnemidophorus parvisocius, new species Cnemidophorus communis australis GADow, 1906, p. 352 (part; some of the specimens from Cuicatlin, Oaxaca). Cnemidophorus sexlineatus gularis, BURT, 1931, p. 117 (part; some of the specimens from CuicatlAn, Oaxaca). 1 I am well aware of the anomaly in the occurrence of two subspecies of a single species at one locality. The nomenclature here is faulty and will be corrected in