Distribution. — This lizard was long thought to be closely 

 restricted to the vicinity of the Colorado River in California, 

 Nevada and Arizona. It has since been found along the 

 western edge of the Colorado Desert and in Lower Cali- 

 fornia. 



In California, it has been collected in San Bernardino 

 (Needles, Turtle Mountains, Blythe Junction, Goffs, Bar- 

 stow,) Riverside (Mecca), Imperial (Meloland, Pilot Knob, 

 Fort Yuma), and San Diego (La Puerta Valley on the east- 

 ern slope of the Cuyamaca Mountains at an altitude of 

 2,200 feet), counties. 



In Nevada, it has been secured at Bunkerville and Call- 

 ville, in Clark County. 



In Arizona, it has been collected in Mohave (Mellen, 

 Needles Peaks), and Yuma (Parker, Ehrenberg, Colorado 

 River twenty miles north from Picacho, and 10 miles be- 

 low Cibola, and at Pilot Knob, Gila City, Yuma), counties. 



In Lower California, it has been found 85 miles south 

 from Mexicali, and at San Felipe. It has also been recorded 

 from Santa Rosalia, by Mocquard, but I suspect that his 

 specimens may have been U. microscutata. 



Habits. — This long slender lizard is chiefly arboreal, 

 but is sometimes seen on the ground. A favorite attitude 



