Aphids, a'fids, small insects, commonly known as plant lice. An aphid has a pear-shaped, usually green, minute body, seldom one-fourth of an inch in length, with long legs, long feelers, and two pairs of gauzy wings. Plant lice infest vegetation everywhere. Trees, growing field crops, vegetables, wild flowers, and house-plants are full of them. They feed by sucking the juice from tender leaves, buds, and shoots. Some species live on the roots of plants. The grape phylloxera, the pest of the vineyard, is a root aphid that has destroyed thousands of vineyards. There are many species, about two hundred and fifty in the United States. Many leaf blights are due to plant lice. The maple, elm, oak, beech, apple tree, peach tree, cherry tree, cabbage, field corn, and many other plants have plant lice peculiar to each. About the only aid the fruit grower has from nature is the lady-bug, which devours them in immense numbers. An aphid introduced into California from Australia with fruit, becoming a pest, has been held in check by the introduction of a lady-bug from the same locality. Plant lice are noted for the production of honeydew which exudes from their bodies and falls on twigs, leaves, and the earth. Bees and wasps gather it for the honey that can be made out of it. Many species of ants depend on the aphid for food, which they induce it to yield as a cow yields milk. An aphid infesting the roots of Indian corn, and a brownish ant that lives in the soil, work together in a sort of partnership. The ant cares for the eggs and larvae of the aphid, burrowing to the roots of the corn and placing the young aphid on a supply of food. The adult lice supply the ants in turn with food. On the leaves of an American ivy vine passing the window by which this article was written, medium-sized, dark-colored ants may be seen fondling aphids with their antennae and gathering honeydew. The ants live under the house, and seem to run up the stem of the ivy daily, confident of finding food. Each stays a half an hour or so, then marches down again with a contented air. Plant lice multiply rapidly. During the growing season of the year, the female gives birth to countless numbers of young, without their going through the intermediate stage of hatching from an egg. Under favorable circumstances the lice may become so numerous and they suck so much sap, that they retard the growth of a plant or even kill it. Many a conservatory is ruined. Gardeners, fruit growers, and florists get after the lice with soapsuds or spray with a mixture of kerosene and water, well shaken together. The multiplication or reproduction among the aphids is quite complex, but very interesting, and is now engaging the attention of scientists in Europe and in America. In each colony there are usually both winged and wingless individuals, the number of wingless predominating. Both forms are females, and give birth to living young during the spring and summer. In some species the living young is born inclosed in a soft shell. In the autumn, on the approach of cold weather, a generation is produced, including both males and females. The females of this generation are always wingless, but the males may be either winged or wingless. These sexual forms pair, and the female produces eggs which usually survive the winter, and are therefore termed winter-eggs. In the spring these eggs hatch, producing the winged and wingless females referred to above. See ANT; INSECT.