AMPHIBIA AND REPTILIA OF COLORADO 77 



suddenly pointed beyond the eyes; large post-antebrachial plates 



present ; size medium C. g«/am Baird and Girard. 



aa. Under part of the throat without a band of large scales; size moderately 

 large C. tessellatus (Say). 



The color pattern of these three species is so similar and so subject 

 to the same type of variation that a comparative description will per- 

 haps be more effective than individual descriptions of each. 



The typical pattern as shown by the young of all three species is 

 composed of a series of four to eight longitudinal stripes of yellow on 

 a ground color of dark brown or olive. In C. sexlineatus these stripes 

 remain prominent throughout life on the body and the anterior por- 

 tion of the tail. On the posterior portion of the tail they break up 

 and disappear. The spaces between the light stripes are darker than 

 the general ground color. 



The next type of pattern is that of the adult C. gularis. The 

 young of this species are marked much Uke the adult of C. sexlineatus, 

 although the two dorsal hght stripes show a tendency to be less dis- 

 tinct. The adult, however, has irregular rows of Hght spots in the 

 dark area between the longitudinal stripes, and the stripes themselves 

 tend to break down into spots. In some specimens this is completed 

 so that they resemble typical individuals of C tessellatus. 



In the adult C tessellatus the breaking up of the longitudinal stripes 

 is usually complete, so that the t}^ical pattern of this lizard is one of 

 spots, the spots being those between the longitudinal stripes and the 

 remains of the longitudinal stripes. The light spots may even become 

 so prominent as to appear to form the background, thus giving a 

 yellowish background with dark spots. The young of this species 

 are marked much like the adult C sexlineatus. Cope^ gives a series 

 of figures showing the parallel variation of the dorsal pattern of 

 C. gularis and C. tessellatus. 



The ventral parts of all three species are whitish, yellowish or even 

 greenish and the dorsal ground color is subject to the same variation 

 in shades of color that is found in other lizards. The tail when com- 

 plete (most specimens will have lost portions of the tail if they are of 



• Cope, Kept. U.S.N.M., pi. s, 1898. 



