560 



COLLEGE ZOOLOGY 



FIG. 460. The python, Python molurus, devouring 

 a mammal. (From Gadow.) 



western states. 

 There is only one 

 " boa-constrictor " 

 with several varie- 

 ties. It belongs to 

 the genus Boa and 

 its specific name is 

 constrictor. It is a 

 native of tropical 

 South America and 

 reaches a length of 

 eleven feet. Boa- 

 constrictors are 

 docile in captivity 



and therefore preferred by snake " charmers." 



Family COLUBRID^:. This family contains about 90 per 



cent of all living snakes and is so large that it is usually divided 



into three series. 



Series A. AGLYPHA. The snakes placed in this series have 



solid teeth, and no grooved nor perforated fangs. They are all 



non-venomous and are found in every country inhabited by 



snakes. Half a 



dozen of the most 



common species 



found in the United 



States are briefly 



described below. 

 The common 



garter-snake or 



striped snake, 



Thamnophis sirtalis 



(Fig. 461), is usually 



provided with three 



longitudinal yellow 



stripes, one on the 



FIG. 461. The garter-snake, Thamnophis sirtalis. 

 (From Gadow.) 



