APHIDES, or plant lice, as they are usually called, are among the most extraordinary of insects. They are found upon almost all parts of plants—the roots, stems, young shoots, buds and leaves—and there is scarcely a plant which does not harbor one or two kinds peculiar to itself. They are, moreover, exceedingly pro lific, for R.:aumur has proved that one individ ual, in five generations, may become the progen itor of nearly six thousand millions of descend ants. It often happens that the succulent extremities and stems of plants will, in an in credibly short space of time, become completely coated with a living mass of these little lice. These are usually wingless, consisting of the young and of the female only; for winged indi viduals appear only at particular seasons, usually in the autumn, but sometimes in the spring, and these are small males and larger females. After pairing, the latter lay their eggs upon or near the leaf-buds of the plant upon which they live, and, together with the males, soon afterward perish. The genus to which plant lice belong is called Aphis, from a Greek word which signifies to exhaust. The following are the principal characters by which they may be distinguished from other insects: Their bodies are short, oval and soft, and are furnished at the hinder tremity with two little tubes, knobs or pores, from which exude almost constantly minute drops of a fluid as sweet as honey; their heads are small, their beaks are very long and tubular, their eyes are globular, hut they have not eyelets ; their antenna are long and usually taper toward the extremity, and their legs are also long and very slender, and there are only two joints to their feet. Their upper are ly twice as large as the lower wings, are much longer than the body, are gradually widened towards the extremity, and nearly triangular; they are almost vertical when at rest, and cover the body above like a very sharp-ridged roof. The winged plant-lice provide for a succession of their race by stocking the plants with eggs in the autumn, as before stated. These are hatched in due time in the spring, and the young lice ately begin to pump up sap from the tender leaves and shoots, crease rapidly in size, and in a short time come to maturity. In this state it is found that the brood, without a single exception, consists wholly of females, which are wingless, but are in a condition immediately to continue their kind. Their young,
however, are not hatched from eggs, but are produced alive, and each female may be the mother of fifteen or twenty young lice in the course of a single day. The plant-lice of this second generation are also wingless females, which grow up and have their young in due time; and thus, brood after brood is produced even to the enth generation or more. without the appearance or intervention, throughout the whole season, of a gle male. This dinary kind of tion ends in the autumn with the birth of a brood of males and females, which, in due time, acquire wings, and pair; eggs are then laid by these females, and with the death of these winged individuals, which soon follows, the race becomes extinct for the season.—Harris' Insects Injurious to Vegetation. In the case of the oats aphis, we believe they are single-brooded; otherwise their habits are much the same as the other plant-lice, having honey tubes, except that, although these are well devel oped, they emit no honey and therefore are not followed by ants. They are also stated to freeze fast with the plants in the fall and revive in the spring. The mussel-shell orange-scale insect (Aspidiotus aloverin) is found on the orange in Florida, where it does much injury to the orange trees, sometimes killing whole orange groves; it is found, also, on citron and lemon trees, and even sparingly on a catnelia grown under an orange tree. The female scale resem bles the upper half of a miniature brown mussel shell, with its flat side downward on the leaf. These scales, when placed singly and not crowded together, are generally straight in form, but when in clusters, they are curved to suit the inequali ties of the surface or contiguity of the neighbor ing scales. The insect itself is sheltered under the scale, and is of a soft consistence, having the body gradually tapering from near the tail to the anterior part, which ends somewhat obtusely. This insect, like the oyster-shell bark-louse of the North, is single-brooded each season. That is, unlike the plant-lice, they do not propagate for several generations by the fertilization of a common ancestor.