16. HELODERMA 473 



Distribution. This large lizard has been found in many 

 part of Arizona, particularly along the Gila River and its 

 tributaries, but in spite of its conspicuous appearance, its 

 range is still but indefinitely known. 



In Arizona, it has been collected in Cochise (Camp 

 Rucker, Cave Creek, Ramsey Canyon in the Huachuca 

 Mountains, Dunlap's Ranch), Greenlee (Duncan), Graham 

 (Mount Turnbull, Safford), Santa Cruz (Fort Buchanan), 

 Pima (Tucson, Fort Lowell, Ventana Canyon, and the steam 

 pump in the foothills of the Catalina Mountains about 

 eighteen miles north of Tucson), Final (Casa Grande), Gila 

 (San Carlos, Roosevelt Dam, Rice), Maricopa (Tempe, 

 Phoenix), Yuma (desert near La Paz on the Colorado 

 River), and Mohave counties. 



In Nevada, it has been found in Clark (Las Vegas, St. 

 Thomas and the Valley of the Virgin about eight miles be- 

 low Bunkerville) and Lincoln (Meadow Valley) counties. 



Dr. Merriam was told by the Mormons that it occurs 

 rarely in the Lower Santa Clara Valley in Washington 

 County, southwestern Utah, and specimens from that county 

 are in the Harvard Museum of Comparative Zoology and 

 the California Academy of Sciences. 



It may be that it occurs on portions of the deserts of 

 southeastern California, but this is very improbable and as 

 yet no specimens from this area have found their way into 

 museums. 



