CROTAPHYTUS 113 



under excitement the brilliantly colored throat is distended 

 and the huge mouth is sometimes opened in anger." 



"One stomach contained two chewed grasshoppers, and 

 another three orthopterous insects, more or less chewed, and 

 four small beetles." 



Mr. Slevin, in southeastern Arizona, observed that "These 

 lizards are very timid. They seem to come out late in the 

 afternoon, and then appear on the tops of boulders, where 

 they may be seen bobbing up and down as many lizards do. 

 This seem.s to be distinctively a rock-loving species, while 

 C. wislizetiil is found on the ground." 



IVIr. Dwight Franklin writes: "Last summer it was my 

 good fortune to be able to study Bailey's Collared Lizard 

 (Crotaphyltu collaris) in the Painted Desert of northern 

 Arizona. Those which I observed were found only in 

 localities where the volcanic or other rock occurred in piles, 

 or was scattered over the ground. The lizards were gen- 

 erally seen perched upon one of these rocks. During the 

 cooler hours of the day they were nearly always a dark, 

 dirty gray, but when the air was warm and the lizards 

 became more active, the color changed to a bright emerald 

 green. This was in the country of the sandstone rocks. 

 Where the black lava rock occurred the great majority of 

 the lizards were of the same dark color, even when active 

 and during the sunny part of the day. In this latter country 

 they were a perfect example of protective coloration, but 

 the green ones seem quite conspicuous, unless one could 

 imagine a resemblance to the short grass, which occurred 

 irregularly. 



"I have two specimens in captivity, and notice this same 

 color change during the day. In the morning, or when the 

 air is cool, they lie sluggishly on the bottom of the cage, or 

 under a rock, and at such times they are of this dark color 

 and show no desire to feed. When the sun strikes their 



