THE LIZARDS 145 



Three-Barred Swift, U. thalassina. It is not only 

 the handsomest but the largest of its genus, occasional 

 specimens being two feet long ; of this measurement the 

 slender tail consumes about sixteen inches. Above, the 

 color is rich, dark green, crossed by three sooty black 

 bars on the forward portion of the body. All of the 

 scales are small and of uniform size. 



A pigmy in comparison with the preceding is Stans- 

 bury's Swift, U. stansburiana, which little lizard is 

 found throughout the southwestern United States, lit- 

 erally swarming in many parts of the Colorado Desert, 

 where it scampers over blistering hot rocks in search of 

 insect prey. The scalation is uniform and granular, 

 and the usual coloration is dark gray or greenish with 

 small dark, rounded blotches surrounded by bluish dots. 

 A mature specimen is about five inches long, of which 

 the tail occupies about two and a half inches ; a specimen 

 like this would have a body five-eighths of an inch wide 

 and a head showing a width of half an inch. 



As an example of those Small-scaled Swifts char- 

 acterized by several rows of greatly enlarged scales on 

 the central portion of the back, we may take the White- 

 Bellied Swift, U. symmetrica. Most specimens have 

 an orange yellow throat; the glaring blue patches so 

 persistently present on the throat and abdomen of the 

 males of other species, are usually absent. The illustra- 

 tion shows the arrangement of the enlarged scales ; they 

 are distinctly keeled. Common in the desert regions of 

 Arizona and eastern California, this lizard is six inches 

 long when fully grown. Its ashy hue, with narrow, 

 wavy cross-bands renders it an inconspicuous object as 

 it basks on the rocks. 



Receiving a small box from Arizona, the writer slid 

 back the lid and was startled by a furious scramble of 



