In its excursions over the trunks and larger limbs of trees the Black and White Creeper is certainly not looking for vegetable food, and only a trace of such matter has been found in the stomachs examined. The food is chiefly insects but considerable numbers of spiders and daddy-long-legs also are eaten. Beetles, caterpillars, and ants are the larger classes of insect food, but moths, flies, bugs, and a few hymenoptera also are eaten. Among forest enemies that have been found in stomachs of this species are round-headed wood borers, leaf beetles, flea beetles, weevils, bark beetles, leaf hoppers, and jumping plant lice. The hackberry caterpillar, the hackberry psyllid, an oak leaf beetle _Xanthonia 10-notata_, and the willow flea beetle, are forms specifically identified. Observers have reported this warbler to feed also upon ordinary plant lice, and upon larvae of the gypsy moth. Forbush (1929) adds the following observation: "The food of this bird consists mostly of the enemies of trees, such as plant-lice, scale-lice, caterpillars, both hairy and hairless, among them such destructive enemies of orchard, shade and forest trees as the canker-worm and the gipsy, brown-tail, tent and forest tent caterpillars. Wood-boring and bark-boring insects, click beetles, curculios and many other winged insects are taken. Sometimes when the quick-moving insects escape its sharp bill, it pursues them on the wing but most of its attention is devoted to those on the trees." H. H. Tuttle (1919), speaking of the male parent feeding the young birds, says: "The fare which he provided was composed entirely of small green caterpillars, cut up into half-lengths." _Behavior._--The black-and-white warbler seems set apart from others of the group, perhaps because of its marked propensity for clambering over the trunks of trees and their larger branches. Although, like other warblers, it seems at home among the smaller twigs, it spends a large part of its time on upright surfaces over which it moves easily and quickly, upward, downward, and spirally, with great agility and sureness of footing, constantly changing direction, and not using the tail for support. As it scrambles over the bark, it switches from side to side as if at each hop it placed one foot and then the other in advance, and even on slim branches it hops in the same way, the tail alternately appearing first on one side of the branch and then on the other; it reminds us of a little schoolgirl swishing her skirt from side to side as she walks down the street. The bird is alert and watchful, and if it starts an insect from the bark, or sees one flying near, it may pursue it and catch it in the air.