92 BULLETIN 199, UNITED STATES NATIONAL MUSEUM 



Range. — From Kansas south to Louisiana, west to the Pacific, as far 

 north as central Oregon, and southward into northern Mexico. 

 Absent from the northern Great Plains and some mountainous areas. 



Species. — Four, with five forms recognized, all but one {C. c. collaris) 

 occurring in Mexico. 



KEY TO MEXICAN SPECIES OF CROTAPHYTUS 



1. Black ring or rings about neck complete or incomplete; body pattern not 



reticulated 2 



No black ring about neck, occasionally a black line present on shoulder; dorsal 

 pattern boldly reticulated reticulatus (p. 93) 



2. Collar formed of a single bar or ring; snout more elongate insularis (p. 93) 



Collar formed of 2 rings, one or both incomplete 3 



3. Tail more distinctly compressed; 4 or 5 scale rows between suboculars and 



labials, and slightly enlarged scales on the middorsal line on tail. 



dickersonae (p. 93) 

 Tail not or scarcely discernibly compressed; minimum scale rows between sub- 

 oculars and labials 2 (rarely 3) ; scale rows between supraorbital areas 2 (or 

 rarely 3) collaris baileyi (p. 92) 



CROTAPHYTUS COLLARIS BAILEYI " Stejneger 



Crotaphytus baileyi Stejneger, North Amer. Fauna, No. 3, 1890, p. 103, pi. 12, 



fig. 1. 

 Crotaphytus collaris baileyi, Stone, Proc. Acad. Nat. Sci. Philadelphia, 1903, p. 



30. — Van Denburgh, Occ. Pap. California Acad. Sci., No. 10, 1922, pp. 



104-114; pi. 7.— Smith, Handbook of lizards, 1946, pp. 170-172, pi. 33. 

 Crotaphytus collaris Burt, Occ. Pap. Mus. Zool. Univ. Michigan, No. 196, 1928, 



pp. 1-19 (part). 

 Crotaphytus collaris collaris, Smith (nee Say), Univ. Kansas Sci. Bull., vol. 22, 



1935, p. 143, pi. 24, fig. 1. 



Type.—U.S.^.M. No. 15821; C. Hart Merriam and Vernon Bailey 

 collectors. 



Type locality. — Painted Desert, Little Colorado River, Ariz. 



Range. — Southern Idaho and Oregon southeastward through eastern 

 California and northern Baja California to San Luis Potosl. Re- 

 ported in Mexico from Baja Calijornia: San Salada, Trinidad, Las 

 Palmas Canyon, Comondu, La Purisima, 6 miles and 33 miles north of 

 Canipole, et cetera; Chihuahua: Chihuahua, Carmen, Progreso, San 

 Buenaventura; Durango: 6 miles northeast of Pedricena; Coahuila: 

 Villa Acuna, Monclova, 4 miles west of Saltillo, Cuatro Cienegas, 

 Pueblo Nuevo, AUende; Nuevo Leon: Pesqueria Grande, Santa Catar- 

 ina; Sonora: Hermosillo, Sierra Tule, Los Nogales, Rio Grande 61 

 miles south of Los Nogales; San Luis Potosi: 30 miles north of Mate- 

 huala, Presa de Guadalupe, 



M With sufficient series it is probable that certain populations now associated with baileyi and collaris will 

 be recognized as other subspecies. For instance, certain specimens from San Luis Potosl have three scale 

 series between the supraocular regions. C. collaris collaris may occur. 



