232 VERTEBRATE ANIMALS OF THE UNITED STATES 



5. catenatus (Rafinesque) . Massasauga (Fig. 126). Length 800 

 mm. ; tail 100 mm. ; color light brown, with a middorsal series of 30 to 36 

 irregular dark brown blotches, each one edged with white, and 3 similar 

 lateral series; belly mottled brown; melanistic coloring not uncommon; 

 scales in 23 or 25 rows; upper labials 11 or 12: western 

 New York to Nebraska; southward into Texas and 

 Mexico; in wet fields and swamps, feeding on frogs and 

 other small animals; bite very dangerous. 





/<) 



Subspecies of S. catenatus 



S. c. catenatus (Raf.). Scales in 25 rows; colors 

 _ darker; blotcheslarger: eastern and central parts of 



Ir ur u s catenatus range. 



{from Cope). ^ ^ edwavdsi (Baird & Girard). Scales in 23 rows; 



colors paler; blotches smaller: Oklahoma and western Texas. 



S. miliarius (L.). Ground rattler. Length 430 mm.; tail 60 mm.; 

 color gray, yellowish or brown, with a middorsal series of about 40 

 irregular spots or cross bars and i or 2 lateral series of smaller spots on 

 each side; belly white, with numerous dark blotches; scales in 21 to 23 

 rows; upper labials 10 or 11: Atlantic and Gulf drainage from central 

 North Carolina to Texas, and up the Mississippi Valley to Arkansas 

 and Oklahoma; in wet places; the least dangerous of the rattlesnakes. 



3. Crotalus L. Rattlesnakes. Head covered with scales, most 

 species having also small plates between and in front of the eyes; rattle 

 large and composed of at most 14 rings; scales in 23 to 31 rows; upper 

 labials 12 to 16; ventrals about 175; subcaudals undivided: 15 species, in 

 North and South America, 11 in the United States, all very dangerous 

 snakes. The young rattler has no rattle, but a soft horny button at 

 the end of its tail. During its first season it adds one horny ring to 

 the button. In the succeeding seasons it usually adds 3 rings a 

 year, the terminal rings usually becoming lost as the snake gets older. 



Key to the United States Species of Crotalus 



ai Tail all black (except the young of C. horridus). 



bi In the eastern and central States C. horridus. 



ho Along the Mexican border C. molossus. 



a2 Tail crossed with black or dark bands. 



bi In the southeastern and Gulf States C. adamaniens. 



b2 In the States west of the Mississippi. 



Ci With a middorsal series of diamond-shaped markings; in 

 the southwest. 



