8. CALLISAURUS 155 



tail is crossed by bars of brown in females and young, of 

 black at least distally in adult males. The posterior bor- 

 ders of these bars may be undulate proximally but are 

 straight or but little undulate from at least the middle to 

 the end of the tail. The throat is white, more or less 

 clouded with gray. The lower surface of the tail is white 

 with about seven (four to eight) cross-bars of intense black. 

 The belly is whitish. Males have a large blue patch, 

 marked with two oblique wedge-shaped black blotches, on 

 each side, and very rarely a small additional spot. 



The following color description was taken from a fresh 

 male shot at Yuma, Arizona, October 1, 1894: The top 

 of the head is cream j the upper surface of the forelimbs 

 bright lemon yellow j the hind limbs slightly tinged with 

 yellow; neck and foreback pale gray spotted with lighter; 

 back like neck, but suffused with bright lemon yellow which 

 extends down over the sides and changes to orange near 

 the large verdigris green blotches on the sides of the belly. 

 There is a reddish orange area in front of each of these 

 green blotches. The throat is gray with a half-concealed 

 vermilion spot. 



Mr. Camp describes variations in color in specimens 

 from the Turtle Mountains, thus: "In the examples before 

 me the color above grades from pale smoke gray, with 

 white on top of the head and white in spots down the back, 

 to neutral gray with the usual dark dorsal markings. A 

 specimen taken in the zone of drifting sand below Blythe 

 Junction is the lightest of the lot, and some taken upon a 

 mesa covered with brown lava are among the darkest of 

 the specimens represented. It would appear that in this 

 lizard, as in Phrynosoma, the tone of color is changeable 

 in the individual to suit the surroundings. The throat is 

 dusky in some specimens and light in others. There is a 

 reddish spot behind the arm in the females. The females 



