422 



REPORT OF NATIONAL MUSEUM, 1893. 



Fiji-, r.i. 



DOKSAL COI.OK PATTEHN OF rrOT V T V 



ll.OR PATTERN OF CROTAI.IS 



CiiNFLUEN'J'US. 



Fig. 54. 

 DORSAL COLOR PATTERN OF CROTALUS LEPIDUS. 



No lattlesiiiike occurs in any of 

 tlic West Iiidiji islands i)roper, and 

 only one species appears to be con- 

 rined to South Amciica, where also 

 another sjiecies 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, wliile there are but 

 few localities in wliicli Rattlesnakes 

 do not occur, or did not occur before 

 they were exterminated by man, yet 

 the area inhabited by more than one 

 s])ecies of Crotalus is comparatively 

 very limited. Thus in the southeast 

 the range of the Diamond Rattle- 

 snake, G. adamanteus, is overlapped 

 to a great extent by that of the 

 l>auded Rattlesnake, C. horridus, 

 while in the center of the Union 

 there is jinother limited area in- 

 habited by two species, viz, the 

 Banded Rattlesnake, C. horridus, 

 and the Prairie Rattler, 6'. con- 

 fluentns. 



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. molossiis, C. atro.r, C. conjinentun, 

 C. figris, C. cerastes, C. lepidus, and 

 C. 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 Crotalus extend 

 a short distance into the British 

 possessions, in the western ])art 6'. 

 liicifer and in the central portion (J. 

 confliientus. 



