41 



feeds so exclusively on eggs that it has a mouth especially fitted 

 for containing and breaking them. 1 



There is a genus Dasypeltis among the snakes, the species 

 of which, native to Africa, are believed to live entirely on eggs. 

 The eggs are swallowed whole and broken in the stomach, 

 where teeth which grow out as processes from the vertebrae 

 pierce through the lining of the stomach so far that they seem 

 perfectly fitted for breaking the eggs that pass through it. If 

 these are true teeth it is the only instance of their occurrence 

 in the whole animal kingdom, except in the mouth or on the 



Diagram showing the percentages of food items of pilot snake (Callopeltis obsoletus) for the year: 



11 }4 per cent red squirrels; 2 per cent opossums; 28 per cent birds; 2 per cent birds' eggs (un- 

 determined); 4H per cent weasels; 10 per cent meadow mice (Microtus pennsyhanicus);2 per 

 cent hens' eggs; 21 per cent insects (probably from birds) ; 7 per cent undetermined mammals; 



12 per cent mice (undetermined). (After Surface.) 



jaws. It may be doubted, however, if eggs form the only 

 food of these snakes. 



In New England the larger and more active snakes are most 

 destructive to birds, while most of the smaller species are now 

 considered as beneficial to man on account of their insectivorous 

 habits. The bird-killing snakes will be considered here in the 

 order of their destructivenesss. 



The pilot snake (Callopeltis obsoletus) should not be confused 



1 Ingersoll, Ernest: The Wit of the Wild, 1906, p. 57. 



