130 BULT.KTIX 15 4, I^XITED STATES NATIONAL MUSEUM 



orif^iiially coiiceiwd hy Kiithvcii (1!)()7, j). ^>^u), avIio Avrute that 

 "There is considerable vaiiatioii in size amoii^- the 'J'ucson specimens, 

 so mncli so, in fact, as to have caused their leference to different 

 species. Stejneger after an examination of si)eciniens in this collec- 

 tion, both from Alamogordo and Tncson, still considers the eastern 

 and western individuals as belon<2:in«>- to a sinule form {('. gidmis) 

 as he has always done, bnt Cope (11)00, p. GOG) and Van Denburgh 

 (1896, p. 341) have both referred the larger Tucson specimens lo 

 scalark, although both record guJaris from the same region. From 

 our series it is evident that there is but one species at Tucson, and that 

 the specimens referred to typical gnlaris by Van Denburgh and Cope 

 are in reality not full grown specimens. Since individuals of this 

 size are generally indistinguishable from Alamogordo specimens, I 

 have no hesitancy in referring them to the same species. The differ- 

 ence between them lies in the fact that while those at Tucson often 

 reach a total length of 400 mm. and over, I am convinced that Alamo- 

 gordo specimens seldom exceed 280 mm. The ditference I believe 

 may be attributed to differences in the nature of the habitat * * *. 

 In both localities gularls is strictly a ground form * * * j^j^j j^ 

 is conceivable that the environmental conditions at Tucson may be 

 more favorable for this species than those com})()8ing its habitat at 

 Alamogordo, and tlnis be directly or indirectly the cause of the 

 larger size attained by individuals in tliis locality. If this be the 

 true explanation of the facts in the case it nnist be that the Alamo- 

 gordo specimens are either inhibited from attaining a larger size b}' 

 exigencies of their habitat, or represent a dwarfed race." Scalarls 

 was definitely synonymized with giJaris ( = per plexus) by Van Den- 

 burgh and Slevin (1913, p. 408), who Avrote that "Our series from 

 Tucson and the steam pump include a number of very large indi- 

 viduals with the coloration typical of the form wdiicli has been called 

 scalaris. As we also have specimens intermediate in size and colora- 

 tion, it would appear that scKilaTis is based on very old individuals 

 of gularis.'''' The writer has examined all of the specimens mentioned 

 in the above discussions and fully agrees with the conclusions ex- 

 pressed above. 



Diagnosis. — The Sonoran race runner is distinguished by its 

 possession of four supraoculars, somewhat enlarged dorsal granules, 

 and a uniform dorsal and lateral ground color. When lined, there 

 are from six to eight stripes present, and the third (usually the 

 upper lateral) pair of stripes on each side are often placed closer 

 to each other than to the stripes below them. A widened, yellowish, 

 middorsal streak is never present. The under surfaces are usually 

 wdiite, although sometimes they stain to blackish in preserved ma- 

 terial, but they are never blue or blue-black as in typical specimens 

 of gularis. Certain specimens of perplexus differ from sexllneatus 



