DESTROYERS OF INSECT PESTS 67 



ined. The food consisted of 42.4 per cent animal 

 food and 57.6 per cent vegetable food, divided as 

 follows : 



Animal food Vegetable food 



Per cent Per cent 



Beetles 17 Wild fruit 42 



Caterpillars .... 9 Cultivated fruit 8 



Grasshoppers . . 5 Miscellaneous 7$ 



Flies 3 Total 



Bees and ants. . 3 57$ 



Bugs 2 



Miscellaneous.. 3J 



Total 42J 



The animal food included 223 kinds of insects, 

 and the vegetable food 65 kinds of wild and 10 kinds 

 of cultivated fruit. This food may be classified ac- 

 cording to its value to man in the following groups: 



Total 33 15 52 



Approximately one seventh of the robin's food is 

 composed of materials beneficial to man, one third 

 is composed of insects harmful to man, and about 

 one hah* is composed of neutral elements. 



So far more than sixty thousand stomachs, com- 

 prising over four hundred species of birds have been 

 examined by the Bureau of Biological Survey. 



