26'^ Illinois Stg.te Laboratory of Natural History. 



out fangs or poison glands. Head generally slender, always 

 lacking the lateral pits which characterize our poisonous spe- 

 cies. Pupil of eye round. Cephalic plates covering most of 

 the head. Dorsal scales carinated or smooth. Subcaudal 

 plates in two series. Tail ranging from long to short, always 

 without a rattle. 



This family contains most of our serpents. All are per- 

 fectly harmless to man, but when cornered they often show 

 considerable spirit in defending themselves. The slight 

 wounds which they are able to inflict with their teeth heal 

 almost as readily as scratches from a needle. The spreading 

 adder, a dark form of which is known as the king snake, ap- 

 proaches the moccasin and rattle snakes in shape of head and 

 body, and is very generally believed to be poisorous, — a belief 

 which it encourages by extravagant behavior when disturbed. 

 The food consists of fishes, frogs, mice, birds, and insects. 

 Our species spend most of their time on the ground among 

 vegetation. A few are expert climbers, while many of the 

 common ttrrestrial species swim and dive readily when com- 

 pelled to enter the water. The species of Nerodia and Regina 

 are constantly found about water, where they depend upon 

 fishes for sustenance. The eggs are often placed in loose de- 

 caying vegetable matter, where their development is accelerated 

 by the warmth due to the process of decomposition. Many of 

 our species, perhaps most, or even all, may produce young alive. 



A SYNOPSIS OF ILLINOIS GExN^ERA OF COLUBRID.E. 



1 (15). Dorsal scales carinated. 



2(6). Anal plate entire. 



3 (22). Rostral not wedged between internasals. 



4(5). Two nasals Eutainia. 



5 ( 4). A single nasal, grooved below nostril. 



Tropidoclonium. 



6 ( 2). Anal divided. 



7 (14). Loreal present. 



8 (12). Two nasals. 



9 (26). Rostral normal in shape. 



10 (27). Anteorbitals present, loreal not reaching orbit. 



11 (23). Scales strongly carinated Nerodia. 



