1 62 ECONOMIC ZOOLOGY 



to forget it. Like the copperhead, the rattlers have been practically 

 exterminated in many thickly settled places, but there are few regions 

 of any extent in the country where at least one species may not be 

 found. 



Something over a dozen species are recognized in the United States, 

 nearly all of them falling under the genus Crotalus. 



They vary in size from the terrible Diamond-back C. adamanteus, 

 Fig. 1 06, of the southeastern part of the United States, one of the most 

 deadly of all serpents, which may reach a length of 8 feet and a diame- 

 ter of 4 or more inches, to the Pigmy or Ground Rattler of Florida, 

 Sistrurus miliarius, adult specimens of which may be less than 18 

 inches long; the difference in the effects of the bites of these two 

 species is correspondingly great. 



Since the rattler usually sheds its skin three times a year, and since 

 a new segment is added to the rattle at each shedding, by allowing the 

 "button" and first ring for the first year, the age of the snake may be 

 calculated by the number of segments in the rattle, provided some of the 

 segments, as is often the case, have not been lost. 



The treatment of rattlesnake-bite has been dealt with above. 



It will be seen, then, that it is a comparatively simple matter for 

 anyone to learn to recognize the venomous serpents of his locality, and 

 such information may, at some time, be of vital importance to its 

 possessor. 



Let us now turn to that much larger group, the non- venomous snakes, 

 a number of which will be mentioned briefly. Many will not be men- 

 tioned, either because their economic value is debatable or because of 

 lack of information in regard to their habits. 



The Garter Snakes. Genus Eutania. The Striped Snakes are the 

 most abundant of North American serpents, and are found over 

 the entire continent, wherever snakes are found. The numerous 

 species are extremely variable, but most people that know anything 

 about snakes recognize the garter or ribbon snakes of their region. 

 They are usually small, 2 feet or less in length, and most of them have 

 one or more longitudinal stripes. They all produce their young alive 

 and in large numbers. Since they feed entirely upon cold-blooded 

 animals, frogs, toads, fish, etc., they are not only not useful to the farmer, 

 but should be considered of some negative importance as destroyers of 

 useful animals, though, possibly, the very young snakes may be of use 



