84 BRITISH SERPENTS. 
Food.—The dietary usually given consists of mice, 
lizards (especially slow-worms), small birds and their 
eggs, insects, moles, and ant-eggs. To this list I would 
add the smooth newt, water-voles, and young rats, as 
having come under my own notice. In the Monnow 
Valley the staple articles of diet are mice, slow-worms, 
and, on the banks of the Monnow river, water-voles. 
One of the parts of our snake literature which seems 
Fic. 16.—SLow-worms. 
especially defective is this question of their food- 
supply and its digestion; and particularly difficult is 
it to get authority for the statements which are made. 
There are only two methods of investigation that are 
of any real value 
namely, the actual watehing of the 
reptile feeding out of doors; and secondly, the dis- 
section of the stomachs of adders freshly killed. The 
former method is almost impossible, as no adder will 
allow itself to be watched when feedine: so reliance 
dD? 
