Few plants except those of the lowest orders are exempt from the ravages of aphides or plant lice, though some are injured much more than others. Some species of aphis confine their attention to particular species of plants; others attack several species. Thus the poppy aphis and that which feeds usually on the pink are also found on asparagus.

Aphides in general are wingless, but in the autumn winged specimens of both sexes appear. Theeggs are laid in the crevices of bark and similarly sheltered spots. The insects hatched from the eggs shed their skin several times, but remain wingless. They are all female, and multiply asexually when from four to ten days old. A single aphis produce; about 90 young, and it is stated that 5 generations have been produced between July 12th and August 19th. The fifth generation, if none perished before reproduction, would amount to 6,000,000,000. Another observer has stated that at least 20 generations are produced in warm, moist seasons. The eggs laid by the later generations in early autumn hatch in a few days, producing winged females and a comparatively small number of males. These reproduce sexually, and the eggs are laid in sheltered positions as before mentioned. The color of aphides varies with that of the plant on which they live. The apple aphis, A. mall,is light green; the plum aphis. A, pruni, green or bluish-green, covered with a whitish dust; the rose, A. rosa, is dark green.

Those feeding on the elder, the cherry and the bean are blackish ; those found on the linden are yellow, and the cabbage and white thorn aphides are whitish-gray. On the back of most species are two hollow prominences, the so-called '"honey tubes, "from which exudes a sweet liquid much sought by ants. The latter, by stroking the aphides, increase the flow of this liquid, and are then commonly said to be "milking their cows." The idea that ants destroy aphides is erroneous, however. The aphis feeds by choice on the youngest and softest parts of plants, extracting their juices by means of its long proboscis. The part of the juice not digested exudes from the honey tubes. As the insects are chiefly found on the under side of leaves, the sweet liquid falls and forms the shining substance known as " honey dew" on the upper side of the leaves beneath. Here, being very sticky, it accumulates dust and the cast-off skins of aphides, and in this way closes the pores and injures the plant. It also does harm indirectly by catching from the air the spores of rust and mildew.

A Fruiting Branch of the Satsuma Orange.

To counteract these injurious effects, one of the best means is to keep up the general vigor of the plant by an abundance of plant food. It is also highly important to instantly destroy the first aphides appearing in the spring. Experiments have been made with various remedies, including oxalic acid, benzine, carbolic acid and Nessler's and Koch's fluids (soap solutions containing tobacco and quassia respectively). The last two have proved the most effective. Simple infusions of tobacco and tomato leaves have been found useful. It is necessary for the fluid to come in contact with the aphides. The plants must therefore be carefully sprayed from all directions, or the affected parts dipped in the solution if possible. Unfortunately the solutions, if too strong, are liable to injure the plants. It is therefore desirable to wash them off with water as soon as the insects have been destroyed. Recently a substance called "Schmidt's Nicotina" has come into use in Germany which is said to kill the insects without doing any injury to the plants.

Among natural enemies of the aphides are the ladybird (Coccinella septempunctata) and an ichneumon fly.

The former, as well as its larva, feeds upon aphides and the ichneumons deposit eggs in their soft flesh. - Translated from Rosen Zeitung.