REPTILES 195 



brown; tail whitish; belly reddish: deserts of southwestern States; 

 northward into Nevada and Utah; herbivorous; used for food; often 

 abundant. 



4. Crotaph5rtus Holbrook. Large, brightly-colored lizards with a 

 very long, tapering tail and small granular scales and a neck-fold: 

 5 species, 4 in the United States. 



Key to the Species of Crotaphytus 



ai One or 2 rows of enlarged scales between the orbital areas. 



bi A double black collar on the neck C. collar is. 



ho No collar on the neck C. ret kill at us. 



ao Several rows of small scales between the orbital areas. 



bi Snout short, truncate in profile C. siliis. 



b2 Snout longer C. wislizenii. 



C. collar is (Say). Collared Kzard; mountain boomer. Body short; 

 head very large; length 300 mm. ; tail 200 mm. ; color green or gray, with 

 numerous white or yellow spots; behind the head are 2 black rings, 

 separated by a white or yellowish space; throat usually orange: central 

 and southern Missouri to central California and 

 southwards; northward into Idaho; in dry rocky 

 places; omnivorous; often abundant; it some- 

 times runs on the hind legs, like a kangaroo. 



C. reticulatus Baird. Similar to C. collaris 

 in form and size; color yellowish brown or gray. 



Fig. 102. — Callisajirus 



With a net- work of pale gray or yellow: south- ventraiis {from Cope). 

 western Texas; rare. 



C. wislizenii Baird & Girard. Leopard Hzard. Length 300 mm.; 

 tail 210 mm.; color brown, with black blotches and red dots; back and 

 tail with yellowish or red transverse bands: the Great Basin from 

 eastern Oregon into southern California and Mexico, in desert places; 

 abundant. 



C. situs Stejneger. Similar to C. wislizenii but with a shorter and 

 more truncate snout, and more sharply defined Hght cross bands: San 

 Joaquin Valley. 



5. Callisaurus Blainville. Body stout; tail rather short; neck-fold 

 present: 4 species, i in the United States. 



C. ventraiis (Hallowell) (C. draconoides Cope). Gridiron-tailed 

 lizard (Fig. 102) . Length 1 80 mm. ; tail 100 mm. ; color gray or greenish, 

 thickly spotted with white; 2 rows of large spots on back; under surface 

 of tail of male white, with 4 wide black bars : western Texas to California ; 

 northward into Utah and Nevada; in desert and arid regions; very 

 common; when running it curls its tail over its back. 



