27. HETERODON 



with black, and may number about forty on the body and 

 ten on the tail. These blotches may be nearly obsolete. On 

 the sides are from two to four series of alternating dark 

 spots, more or less distinct. The lower surface is yellowish 

 white with black blotches on the gastrosteges, which usually 

 are entirely black centrally, as are the urosteges. The head 

 is light brown above with a narrow light streak across the 

 frontal and supraocular plates. A second similar but less 

 distinct streak just behind the rostral extends down in front 

 of the eye. There are three dark blotches on the nape and 

 an oblique one behind the eye. 



A living snake of this species, from Arizona, was colored 

 as follows: The color above is a dull brownish yellow. The 

 dark markings on the head and the lower series of lateral 

 spots are olive brown. The dorsal blotches and the upper 

 lateral series are dark brown with black spots on the bases 

 of some of the scales. The chin, gular region, the tips of 

 the gastrosteges and the edges of the lateral scales are 

 white. The centers of the scales of the lowest lateral row 

 are pinkish brown. The upper labials are pale straw yel- 

 low. The lower surfaces of body and tail are marbled with 

 deep lemon yellow and black. The iris is reddish brown. 

 The tongue is black. 



Length to anus 165 267 45 5 470 533 532 



Length of tail 32 38 100 63 76 100 



Distribution. — This snake occurs from southwestern 

 Iowa, Kansas and Nebraska, west to Montana and south to 

 Texas, New Mexico, Arizona and northern Mexico. Baird 

 and Girard (1853) recorded one as having been collected 

 in California by Dr. William Gambel. This specimen 

 probably was mislabeled. In Arizona this species has been 

 collected at Fort Whipple, at White River Canyon, at Min- 

 eral Springs, Sulphur Spring Valley, Wilcox, and in "South- 

 em Arizona." We recently secured a specimen from the 



