360 Bulletin 83 



usually bordered with pale greenish-yellow. The abdomen is pink- 

 ish, or yellowish-white." (Ditmars). This is a rare rattlesnake, 

 found thus far only along the Mexican boundar}^ in Mexico, Texas, 

 New Mexico and Arizona. 



Our chief purpose in giving these details, particularly with 

 legard to the last two species, is in the hope that specimens may be 

 sent to our museum from loyal Arizonians. We, for that matter, 

 would be pleased to receive good specimens of any of the rattle- 

 snakes found in Arizona, of which we have at present only a meager 

 collection. 



The Tiger Rattlesnake (Crotahts figris), is upward of four feet 

 in length, strongly banded on the posterior two-thirds of the body 

 with yellowish-gray and very dark bands. It is found chiefly in 

 barren mountains of the extreme Southwest, i. e., southwestern 

 Arizona and southern California, and was reported common near 

 Yuma in the fiood season of 1905. 



The Horned Rattlesnake (Crofaliis cerastes), is a small but dis- 

 tinctive species with a small horn-like protuberance over each eye. 

 It is well-known by reputation in Arizona, and best known as the 

 "side-winder." The latter name is given to it because of the fact 

 that when hurried it moves by a peculiar looping movement which 

 carries it obliquely sidewise as well as forward, an adaptation to 

 progression over yielding sand. The side-winder is small, two to 

 two and a half feet in length, and is probably found in all desert 

 areas of Arizona, since it is known also in Utah, California and 

 Nevada. It has the reputation of being a very dangerous reptile, 

 due perhaps to agility and a vicious temperament. It is not likely 

 that its poison is diflferent in quality or quantity from that of other 

 rattlers. 



The Pacific Rattlesnake (Crofalus orcgomts), is called the Black 

 Rattlesnake where known in Arizona. Ditmars does not include 

 Arizona in its range, but Dr. J. Van Denburgh of the California 

 Academy of Sciences has secured three specimens ; one from Oak 

 Creek, Coconino County; one from Cave Creek, Maricopa County,^ 

 and one from the Santa Catalina range. Dr. R. H. Forbes, of the 

 Experiment Station, also assures me that he has seen the Black 

 Rattlesnake in the latter mountains. In coloration the Santa Cata- 

 lina specimens appear much darker than the one figured by Dit- 

 mars. This kind reaches a length of about three feet. 



The Prairie Rattlesnake (Crofalus conHuentus), is not included 

 with Arizona's rattlers by Ditmars, and again we are indebted to 



