AMPHIBIA AND EEPTILIA OF COLORADO 67 



mouth black. Markings vary from quite obscure to distinct, and 

 both colors and markings are more vivid at the breeding season. 



Mr. H. G. Smith of the State Historical and Natural History 

 Museum informs us that this species is commonly known as the 

 "Boomer" in western Colorado. It is extremely active and when 

 disturbed often runs on its hind legs. Like most of our Iguanidae, 

 the Collared Lizard is oviparous. One specimen reported by Ditmars 1 

 laid twenty-one eggs early in August. 



Crotaphytus collaris ranges from Idaho south into Mexico, west 

 into California and east into Arkansas. 



Colorado specimens. — University Museum: Rifle Gap, August 5, 1909 

 (245 mm.), A. H. Felger, No. 55; State Historical and Natural History Museum: 

 Grand Junction, August 13, 1905 (255 mm.), Ora Keithley; Grand Junction, May 

 17, 1906 (260 mm.), W. C. Ferril; Colorado Museum of Natural History: Trinidad, 

 May 2, 1911 (300mm.), L. J. Hersey; Trinidad, June 7, 1911 (340 mm.), L. J. 

 Hersey; Trinidad, August 5, 1911 (60 mm.), L. J. Hersey; Trinidad, September 5, 

 191 1 (5 specimens, 250-300 mm.), L. J. Hersey; Stale Teachers' College Museum: 

 Trinidad and Delta, A. E. Beardsley; reported common at Trinidad, by L. J. 

 Hersey. 



Genus SCELOPORUS Wiegmann 



Sceloporus Wiegmann, Isis, p. 369, 1828. 



Scales moderately large, keeled dorsally, with the keeled portion 

 often produced into a sharp point; no gular fold; tail a little longer 

 than the body; ear openings not covered; femoral pores present; 

 supraorbital plates prominent. 



The Spiny Swifts, Sceloporus, are small to moderately large lizards, 

 including some of the most abundant species found in the United 

 States. Species of this genus are found from Central America to 

 Canada, and over the whole of the United States. They feed largely 

 upon small insects and insect larvae. In general color they are gray 

 or brown, lighter below, and the males have a blotch of blue on each 

 side of the abdomen. Two species are recorded from Colorado. 

 Key to the Colorado Species of Sceloporus 



a. Supraorbital plates in four rows; inside row of small plates, second row of 

 large plates, third and fourth rows of small plates. 



5. consobrinus Baird and Girard. 



■ Ditmars, Reptile Book, p. 115, 1907. 



