20 BULLETIN 1355, U. S. DEPABTMEXT OF AGRICULTURE 
Coleoptera. — Considering the enormous numbers of beetles avail- 
able, it is somewhat surprising that not more are eaten. The blue- 
heads manage to seek out enough, however, to make up 13.51 per 
cent of their entire diet. Of this, the ladybird beetles make up 4.88 
per cent, or more than a third. It is certain that there are not a 
third as many ladybird beetles as all other beetles combined; and thus 
it must be considered that the blue-headed vireos, like the warbling, 
^either find these brilliantly colored forms in abundance in their envir- 
onment or else make special search for them, a most undesirable habit 
economically. Roughly, a second third of the total bulk is composed 
of the metallic wood borers, the longicorns. and the click beetles. 
The remaining portion includes, among others, the weevils, which 
comprise 1.8 per cent of the food. 
Hyj7ienoj)tera. — With the exception of the month of March, mis- 
cellaneous liymenopterans were eaten in quantities varying from 1.75 
per cent (in January) to 16.78 per cent (in May). Remains of no 
very important insect pests were found among the fragments from 
the stomachs, though several sawfhes and ants were detected. The 
average for liymenopterans eaten during the year was 6.86 per cent. 
Diptera. — Two-winged flies make up the comparatively small per- 
centage of 4.29, or less than that of the single family of coccinellids 
(ladybird beetles), although flies are almost universally present. The 
flies of the woods are in general of little importance, excepting the 
bloodsucking forms: and as these are not often found in the stom- 
achs, the economic importance of the dipterans in the food is slight. 
Other insects. — Among the insects eaten which do not belong in the 
above classes are the stone flies, dragon flies, grasshoppers, crickets, 
and locusts (6.56 per cent for the year) . In January this group is one 
of the most important, making 21.76 per cent of the food. February 
shows a slight decrease (18.38 per cent), and from then on the per- 
centage varies from 1.24 in May to 7.5 in August. In general, this 
group is of no more importance economically than the dipterans. 
Other animal food. — Spiders run very evenly in the food of birds of 
this species and are probably picked up whenever occasion offers. 
With the exception of February, when they amount to but 0.18 per 
cent, spiders are present in percentages varying from 1.51 to 5.55. 
the last figure representing August. The average of 2.63 per cent may 
be taken as a fair estimate of the quantity of this type of food eaten 
by the blue-headed vireos. 
Snails are sometimes eaten, but so rarely that they are not to be 
considered an essential part of the diet (yearly average, 0.25 per 
cent) . 
VEGETABLE FOOD 
During the winter months vegetable food is of considerable impor- 
tance in the diet of this bird. In January nearly a quarter of the 
total was of vegetable origin (24.37 per cent) ancl in February less 
than a tenth (9.81 per cent). From March to and including August 
no trace of vegetable matter appeared in the food, but by November 
it formed 4.44 per cent. For the most part it was in "the form of 
fleshy fruits, such as wild grape, dogwood, viburnum, and wax 
myrtle. No cultivated fruit was identified, and it is practically 
certain that none is eaten. 
