422 



REPORT OF NATIONAL MUSEUM, 1893. 



Xo rattlesnake occurs in any of 

 the West India Islands proper, and 

 only one species appears to be con- 

 fined to South America, where also 

 another species occurs, the range of 

 which, however, extends into south- 

 ern Mexico. 



Within the United States not less 

 than ten species, with several sub- 

 species, are found; but their dis- 

 tribution within that area is very 

 uneven. Thus, while tliere are but 

 Pi„_;5j few localities in which Eattlesnakes 



DORSAL COLOR PATTERN OF cROTALus MOLOfsus. ^jq ^jq^ occur, or did uot occur before 



they were exterminated by man, yet 

 the area inhabited by more than one 

 species of Crotabis is comparatively 

 very limited. Thus in the southeast 

 the range of the Diamond Rattle- 

 snake, C. aclamanteus, is overlapped 

 to a great extent by that of the 

 Banded Rattlesnake, C. horridits, 

 while in the center of the Union 

 there is another limited area in- 

 habited by two species, viz, the 

 Banded Rattlesnake, C. horridus, 

 and the Prairie Rattler, C. eon- 

 fiuentus. 



As we approach the Mexican 

 boundary and the northward exten- 

 sion of the Sierra Madre the density 

 of the distribution of the species 

 increases rapidly, until in southern 

 Arizona we find no less than 7 dif- 

 ferent species of Rattlesnakes, viz: 

 C. molossus, G. <itro.x\ C. coHjiuentHS, 

 C\ tigris, G. cerastes, G. lepidus, and 

 ('. mitcheUii pyrrhus, out of a total of 

 10 species inhabiting the entire area 

 of the United States. 



North of our northern boundary 

 only two species of Grotalus extend 

 a short distance into the British 

 possessions, in the western part G. 

 lueifer and in the central portion G. 



DORSAL COLOR PATTliKN OF CEOTALVS LEPIDUS. COUff HOtt l(S. 



Fig. 52. 

 DOESAL COLOR PATTERN OF CROTAT.r 



Fifi. 53. 

 DOR.<AL COLOR PATTERN OF CROTALUS 



COXFLUENTUS. 



