424 



KANSAS UNIVBRSITY SCIENCE BULLETIN. 



Logan, Gove and Scott counties I did not see a specimen of 

 Sistrvriis. Dr. S. W. Williston, who has spent six summers on 

 the plains of western Kansas, informs me that he never saw a 

 specimen of Sistrurus there. If it occurs in the western part of 

 the state it is rare. Abundant in middle part of state. Rare 

 in eastern part. 



CROTALUS LiNN.Eus. 



Crotaliis Lincivus, Syst. Nat., 10th ed., 1758, p. 214; 12th ed., 1766, p. 572. 



Caudisona Laurenti, Spec. Syn. Kept., 1868, p. 92. 



A jointed rattle at the end of the tail. The top of the head 

 covered with scales. Plead broad and neck contracted ; sub- 

 caudals not divided. 



Only two species of this genus are found in Kansas. These 

 snakes are much larger than the Sistnn-us and are consequently- 

 more dangerous. 



I. — Tail black; dorsal pattern consisting of dark, double-chevron-shaped bands. 



.\ dark-colored snake C. horridus. 



II. — Tail with brown or indistinct bands. Three rows of dark dorsal spots. A 

 light postocular band reaches the second row of scales above the angle of 

 the mouth. A light-colored snake C. coiijlurntus. 



Crotalus horridus Linn;i?us. 



Banded or Timber Rattlesnake. 



Crotalus horridus Linn^us, Syst. Nat. 12th ed., I, 1766, p. 372; Cope, Proc. 



Acad. Nat. Sci. Phila., 1859, p. 338. 

 Crotalus durissus Latreille, Hist. Kept., Ill, 1801, p. 190. 



Fig. 38. 

 Crotalus horridus Linn. 



Rows of scales 23-25, all strongly keeled, excepting the first 

 two rows, which are faintly keeled. Top of head covered with 



