40 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY. 



A small number of flies, grasshoppers, and dragon-flies make up a 

 little more than 3 percent of the miscellaneous insects. Spiders were 

 eaten to somewhat less than 2 percent. 



CASSIN VIREO. 



(Yireo solitarius cassini.) 



This is another of the tree^ foragers living in summer in orchards, 

 canyons, and forests. 



Its food consists of the same elements as that of the last-described 

 species, but in somewhat different proportions. Forty-six stomachs 

 were examined, taken in every month from April to November. They 

 afford at least a fair indication of the food for those months. 



Vegetable food. — The vegetable food, which was only a little more 

 than 2 percent of the total, was made up of leaf galls, seeds of poison 

 oak, and a few bits of rubbish. Not a trace of fruit was found. 



Animal food. — The animal matter amounts to nearly 98 percent of 

 the whole. Hemiptera are the largest item and amount to nearly 51 

 percent. The various families represented are those of the squash- 

 bugs, leaf-bugs, stink-bugs, shield-bugs, leaf-hoppers, tree-hoppers, the 

 jumping plant-lice, and scales. The latter are represented as usual by 

 the black olive scale, which was contained in four stomachs. Caterpil- 

 lars, with a few moths, are next in importance and form more than 

 23 percent of the whole food. They were eaten in every month and 

 are evidently a favorite diet. 



Hymenoptera are eaten much more largely by this species than by 

 the last. They amount to over 7 percent, and are mostly wasps, with 

 a few ants. This record, however, is likely to be modified by further 

 investigation. 



Ladybird beetles were eaten to the extent of a little less than 6 

 percent, which is quite reasonable as compared with the record of the 

 warbling vireo. It is, however, much greater than that of any bird 

 outside the present genus, except the pygmy nuthatch, and in the 

 case of that bird the evidence is too meager to be accepted at its face 

 value. Other beetles amount to a little more than 3 percent of the 

 food, and are mostly weevils and small leaf-beetles (Chrysomelidae). 

 A few flies, grasshoppers, and other insects amount to somewhat more 

 than 2 percent, and these, with 4 percent of spiders, make up the 

 remainder of the animal food. 



SUM MAE Y. 



In glancing over this record of the Cassin vireo it appears that 

 bugs are the favorite food, as shown by the numbers consumed; but 

 caterpillars, though second in quantity, are eaten with greater regu- 



