The Rattlesnakes 



writer has adopted for them the popular title of the Pigmy Rattle- 

 snakes. 



The Pigmy Rattlesnakes may at once be distinguished 

 from other rattlers, by the scalation of the top of the head. The 

 head is covered with large, symmetrical shields, arranged like 

 those of the harmless or colubrine snakes. But from the latter 

 the Sistruri may be told at a glance by the rattle and the char- 

 acteristic pit of the family Crotalidce. 



The species found in the United States may be concisely 

 defined : * 



Key to the Pigmy Rattlesnakes 



I. Ground-colour brownish. Large, dark saddles on the 

 back and a smaller series on side. 



Blotches of the back in close formation; those of the 



sides of moderate size. MASSASAUGA, S. catenatus. 



Distribution. Western New York to Nebraska; 



Canada to Kansas, 

 f Blotches of the back smaller and more separated; those 



of sides very small. 



EDWARD'S MASSASAUGA, 5. catenatus variety edwardsii. 

 Distribution. Southwestern United States. 



II. Ground-colour gray. Large black saddles on back and 

 a smaller series on sides. 



Blotches on back well apart. A reddish streak from 

 behind the head. 



SOUTHERN PIGMY RATTLESNAKE, S. miliariuS. 



Distribution. Southeastern United States. 

 Following are detailed descriptions: 



THE SOUTHERN PIGMY RATTLESNAKE 



Sistrurus miliarius, (Linn.) 



A very small species, though stout of form, with distinct, 

 flattened head. The body tapers gradually to a thin tail, which 

 is provided with a minute rattle. 



Colouration. Dark ashy gray, with a series of large, black 

 blotches on the back, these irregularly rounded and separated 

 on the central portion of the back by reddish spaces. The 



* One other species, 5. ravus, inhabits Mexico. 



t Another variety, technically called S. catenatus consors has been 

 described. The pattern is like that of Edward's Massasauga, but the 

 number of scale rows is 25 (like the typical form). Edward's Massasauga 

 has 23 rows of scales. 



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