_Urosaurus bicarinatus tuberculatus_, Mittleman, Bull. Mus. Comp. Zool., 91:169, September, 1942. Twenty-six km. S of Arteaga; Cascada Tzararacua (2); Chupio; Coahuayana; Coalcomán (8); El Sabino (2); Jungapeo; La Orilla (2); La Placita (4); Playa Azul (4); Pómaro (2); San Salvador (16);? Tupátaro; Uruapan (12); Tzitzio; Zamora. The known distribution and geographic variation of _Urosaurus bicarinatus_ in southwestern México presents a confused picture. In general rugosity, specimens from the coastal region of Michoacán (Coahuayana, La Orilla, La Placita, Playa Azul, and Pómaro) resemble _U. bicarinatus tuberculatus_ to the north along the Pacific coast. Furthermore, specimens from the coast have less stippling in the gular region than do those from the Sierra de Coalcomán and the slopes of the Cordillera Volcánica. Specimens from the mountains have greatly carinate enlarged dorsals, large lateral tubercles, and heavily stippled throats; in these characters they resemble specimens from Morelos, Guerrero, and Oaxaca. As mentioned by Peters (1954:14), some specimens from La Orilla and San Salvador are like _U. bicarinatus bicarinatus_ in certain characters, and one specimen has the blue ventral patches restricted to the sternal area, a characteristic of _U. bicarinatus anonymorphus_ of Oaxaca and eastern Guerrero. Examination of all available specimens from Michoacán indicates that the nature of the dorsal scales is of little value in separating the subspecies. The specimens from Michoacán are here provisionally referred to _U. bicarinatus tuberculatus_, because cursory examination of specimens from several localities between Nayarit and Oaxaca shows that there are only minor differences between the named populations. Individuals from the northern part of the range are more rugose and have larger blue ventral patches and less gular stippling than those from the south. In Michoacán _Urosaurus bicarinatus tuberculatus_ is found in wooded areas, not in open scrub forest, in the coastal area to elevations of about 900 meters, and along the slopes of the Cordillera Volcánica and the southern edge of the Mexican Plateau at elevations from 1000 to 1700 meters. The record for Tupátaro probably is erroneous, for no other specimens of this species are known from the central plateau. Essentially, the distribution of this species parallels that of _Sceloporus utiformis_, a strictly terrestrial species. _Urosaurus bicarinatus tuberculatus_ lives on tree trunks. Below 1000 meters in the Tepalcatepec Valley _Urosaurus bicarinatus tuberculatus_ is replaced by _Urosaurus gadowi_. ~Urosaurus gadowi~ (Schmidt) _Uta gadovi_ Schmidt, Amer. Mus. Novitates, 22:3, December 1, 1921.--Cofradía, Jalisco, México (in error) = Cofradía, Michoacán, México (Duellman, 1958b:49). _Urosaurus gadowi_, Mittleman, Bull. Mus. Comp. Zool., 91:154, September, 1942.