26 BULLETIN" 1355, U. S. DEPARTMENT OF AGRICULTURE 
Orthoptera. — No other species of vireo of which the food habits 
are known takes so large a quantity of such bulky insects as grass- 
hoppers, locusts, and the like. Though the present species is one 
of the smallest in size, it includes in its diet for July enough of the 
orthopteroids to make 34.88 per cent of that month's food. This 
form of food is essentially a summer type, none being taken in May, 
a considerable quantity in June, and 21.87 per cent in August. The 
average percentage for the summer months is 18.52. 
Lepidoptera. — About one-fifth (20.63 per cent) of the subsistence 
of the Bell vireos during the summer is made up of caterpillars, and 
of adult moths and butterflies, and their eggs. As the last-named 
items are rarely found in a stomach, the figures given refer mainly 
to the first two. Caterpillars do not become an important factor in 
the economy of the birds before June, although a few (1.67 per cent) 
are eaten in May; in each of the months July and August the con- 
sumption amounts to about 25 per cent, and the average for the 
Fig. 9.— Yearly summary of the various items in the food of the Bell vireos ( Vireo belli, subspp.), based on 
the analysis of the contents of 52 stomachs 
four months is 15.89 per cent. Lepidopterans in other stages make 
up 4.74 per cent of the food, the consumption being heaviest in July 
(11.07 per cent). 
Coleoptera. — Beetles of all kinds make up 15.26 per cent of the 
summer food of the Bell vireos. Ladybird beetles are taken in 
moderate numbers and form 2.19 per cent of the total food. Weevils 
(6.09 per cent) and leafbeetles (3.98 per cent) account for the most of 
remainder of the coleopterous food. 
Eymenoptera. — Hymenopterans of all sorts (bees, wasps, etc.) 
amount to 6.44 per cent of the total diet during the summer months. 
The increase in consumption is at first slight, May and June being 
represented by 2.33 and 3.2 per cent, respectively. In July a sharp 
rise is noted to the maximum of 12.83 per cent; in August it is only 
7.38. The evidence at hand probably gives a fairly correct view of 
the facts. 
