28. COLUBER 



marbled with bright yellow and black. Throat black with 

 scattered spots of yellowish orange. About the twentieth 

 gastrostege the light color increases in amount and the 

 black becomes restricted to small blotches that become fewer 

 posteriorly, only a few small, widely scattered spots being 

 present on the posterior three-fourths of the body length 

 and none on the tail. For most of the length the belly is 

 a yellow orange tint, becoming a dark orange tint on the 

 posterior one-fourth of the body and on the tail. 



Length to anus 303 541 723 8+0 1095 1300 1365 



Length of tail 96 185 242 300 345 430 435 



Remarks. — There has long been doubt as to whether 

 the black specimens are merely melanistic individuals or 

 really represent a distinct species. There seem to be no 

 structural differences. Scale-counts and proportions are the 

 same. Dark specimens occur in Lower California and on 

 Tiburon Island as well as in Arizona. All this favors re- 

 garding them as a melanistic phase of the Red Racer, but 

 the fact that two black specimens were found mating, near 

 Tucson, is very interesting, since it would seem to indicate 

 that they may really represent a distinct species. The final 

 answer to this question must await additional evidence, but 

 it seems best, for the present, to regard the black and the 

 red snakes as one species. 



Distribution. — The Western Whip Snake or Red Racer 

 has its true home in the deserts of Arizona, Nevada, Utah, 

 California and Lower California, but ranges into northern 

 Sonora (Hermosillo), and the San Joaquin Valley and 

 coast region of southern California. 



In California, it has been taken in Imperial (Fort Yuma, 

 Colorado Desert, Pilot Knob), San Diego (Mountain 

 Spring, Campo, San Diego, Agua Caliente, San Felipe Val- 



