This large diurnal species inhabits open scrub forest and cultivated terrain from sea level to about 1650 meters. On the Mexican Plateau it is known from the area around Lago de Chapala, to which it possibly gained access through the valleys in the headwaters of the Tepalcatepec drainage. Specimens from southern Michoacán have been reported previously by Peters (1954:28) and Duellman (1954b:16) as _Masticophis flagellum lineatus_. ~Masticophis taeniatus australis~ Smith _Masticophis taeniatus australis_ Smith, Jour. Washington Acad. Sci., 31:390, September 11, 1941.--Guanajuato, Guanajuato, México. Tacícuaro (2); Zamora. This species reaches the southern limit of its distribution in the state of Michoacán. The limited ecological data available suggest that the species inhabits the open mesquite grassland of the Mexican Plateau. ~Oxybelis aeneus auratus~ (Bell) _Dryinus auratus_ Bell, Zool. Jour., 2:324, 1825.--México. Type locality restricted to Tehuantepec, Oaxaca, México, by Smith and Taylor (1950a:340). _Oxybelis aeneus auratus_, Bogert and Oliver, Bull. Amer. Mus. Nat. Hist., 83:381, March 30, 1945. Coahuayana; El Sabino (4); between Las Tecatas and Las Higuertas; between Los Pozos and La Ciénega; Playa Azul; Pómaro (2); between Pómaro and Maruata (2); Punto San Telmo; Río Tizupan. On the basis of the number of specimens seen and collected on the seaward slopes of the Sierra de Coalcomán, this is a common snake there. Most specimens were collected in tropical semi-deciduous forest; others were collected in oak forest to an elevation of 1700 meters. Apparently _Oxybelis_ does not inhabit the lower parts of the Tepalcatepec Valley; the only specimens from the inland area are four from El Sabino, which is situated at about 900 meters on the slopes of the Cordillera Volcánica. One individual was seen in gallery forest near Limoncito at an elevation of 730 meters on the northern slopes of the Sierra de Coalcomán. ~Pituophis deppei deppei~ (Duméril) _Elaphis deppei_ Duméril, Mem. Acad. Inst. France, 23:453, 1835.--México. Type locality restricted to San Juan Teotihuacán, México, México, by Smith and Taylor (1950a:334). _Pituophis deppei deppei_, Stull, Occ. Pap. Mus. Zool. Univ. Michigan, 250:1, October 12, 1932. Carapan (2); Morelia; Tacámbaro; Tacícuaro; Zacapu. Duellman (1960b) showed that the widespread species _Pituophis deppei_ was composite and that the "lined subspecies" actually represented another species, _Pituophis lineaticollis_. _Pituophis deppei_ occurs only on the Mexican Plateau; in Michoacán it inhabits mesquite grassland and oak-bunch grass associations between 1900 and 2200 meters. ~Pituophis lineaticollis lineaticollis~ (Cope)