To protect its foliage from being eaten by hungry cattle, the rose goes armed into the battle of life with curved, sharp prickles, not true thorns or modified branches, but merely surface appliances which peel off with the bark. To destroy crawling pilferers of pollen, several species coat their calices, at least, with fine hairs or sticky gum; and to insure wide distribution of offspring, the seeds are packed in the attractive, bright red calyx tube or hip, a favorite food of many birds, which drop them miles away. When shall we ever learn that not even a hair has been added to or taken from a blossom without a lawful cause, and study it accordingly? Fragrance, abundant pollen, and bright-colored petals naturally attract many insects; but roses secrete no nectar. Some species of bees, and a common beetle (Trichius piger) for example, seem to depend upon certain wild roses exclusively for pollen to feed themselves and their larvae. Bumblebees, to which roses are adapted, require a firmer support than the petals would give, and so alight on the center of the flower, where the pistil receives pollen carried by them from other roses. Although the numerous stamens and the pistils mature simultaneously, the former are usually turned outward, that the incoming pollen-laden insect may strike the stigma first. When the large bees cease their visits as they may in long-continued dull or rainy weather, the rose, turning toward the sun, stands more or less obliquely, and some of the pollen must fall on its stigma. Occasional self-fertilization matters little. If plants have insect benefactors, they have their foes as well and hordes of tiny aphids, commonly known as green flies or plant lice, moored by their sucking tubes to the tender sprays of roses, wild and cultivated, live by extracting their juices. A curious relationship exists between these little creatures and the ants, which "milk" them by stroking and caressing them with their antennae until they emit a tiny drop of sweet, white fluid. The yellow ant, that lives an almost subterranean life, actually domesticates flocks and herds of root-feeding aphids; the brown ant appropriates those that live among the bark of trees; and the common black garden ant (Lasius niger), devoting itself to the aphis of the rose bushes, protects it in extraordinary ways, delightfully described by the author of "Ants, Bees, and Wasps." In literature, ancient and modern, sacred and profane, no flower figures so conspicuously as the rose. To the Romans it was most significant when placed over the door of a public or private banquet hall. Each who passed beneath it bound himself thereby not to disclose anything said or done within; hence the expression sub rosa, common to this day.