FOOD HABITS OF THE VIREOS 17 
in size between the pentatomids and the smaller leaf-feeding bugs, 
the actual number of leaf hoppers and other small bugs is probably 
as great as that of the stink-bugs or even greater. 
Coleoptera. — Beetles of all kinds, making up 12.9 per cent of the 
yearly food, stand third in the diet. Ladybird beetles, usually 
plentifully found in the stomachs of vireos, in this species amount to 
less than 1 per cent of the total. The rest of the insects may be classed 
as injurious, or potentially so. The weevils, or snoutbeetles, make 
4.23 per cent, or about one-third of all the coleopterans eaten. The 
wood-boring forms belonging to the families Buprestidae and Ceram- 
bycidae and the plant-feeding Elateridae, together form more than 
one-fourth of the beetle food, or 3.57 per cent. Dung beetles and 
leaf chafers (Scarabaeidae) amount to 1.84 per cent, whereas leaf 
beetles (Chrysomelidae) and ladybird beetles (Coccinellidae) make, 
respectively, 0.82 and 0.62 per cent of the yearly food. Fragments 
of beetles that could not be associated with any of the above-men- 
tioned families together make up 1.82 per cent of the whole. 
Diptera. —Two-winged, or true, flies, make up 7.36 per cent of the 
yearly subsistence, of which the major part is consumed in May and 
June. More than one-fourth of the stomachs of the yellow-throat 
examined contained remains of flies, although in most cases the 
insects were not in condition to permit more specific identification. 
Midges ( Chironomidae) and horseflies (Tdbanus) were among the 
dipterans eaten. 
Hymenoptera. — No honeybees were identified in the 160 stomachs 
of the yellow-throated viero examined, but other bees, as Andrena 
or Halictus, were found. Sawflies and ichneumon flies also were 
determined. Other hymenopterans were detected in lesser quantity , 
and together the insects of this order made up 5.07 per cent of the 
annual food. 
Other insects. — The rest of the insect food amounts to 4.92 per cent r 
about equivalent to the bulk hymenopterans taken. Under this head 
are gathered all records of grasshoppers, crickets, locusts, and dragon 
flies and other water-inhabiting forms. In the food of the yellow- 
throated vireo this group is not of very great importance economically. 
Other animal food. — Spiders, with the few snails the bird happened 
on, made up 2.38 per cent of the food. Snails were taken during 
April only and then only to the extent of 0.36 per cent, which, trans- 
lated into a yearly percentage, makes the insignificant total of 0.06. 
Among the spiders eaten, the Attidae, or jumping spiders, were the 
most common. Species of Phidippus were determined four times, 
and fragments referable to family only were found in six other stom- 
achs. The tetragnathids, which infest marshy localities, were iden- 
tified twice, and once a minute pseudoscorpion of the genus Chthonius 
was detected. In general, the spiders eaten are only slightly beneficial. 
VEGETABLE FOOD 
The yellow-throated vireo eats comparatively little vegetable food, 
practically none during April and May, none during June and July, 
less than 2 per cent in August, and less than 9 per cent in September. 
The average for the year is only 1.74 per cent. Among the items 
specifically determined were sassafras berries and seeds of wild grapes. 
No cultivated fruit of any kind was found. 
50209— 25f 3 
