aphis, aphis (plural aphides, aphides)

[Mod. Lat.] It Entom. Plant louse. A genus of insects, the typical one of the family Aphide. contains those soft pulpy little animals, winged or wingle , and with long antennæ, which are seen beneath the leaves, or in curled-up leaves, or in the axils of many plants, or even on the roots of some. Sometimes, as in the case of the elm, their destruc tive operations upon a leaf raise a gall of considerable size. The species are very numerous, and are generally called after the plants on which they feed, as A. rose, the APHIDES. aphis of the rose; A. fabæ , the bean apis; A. bra icæ , the cabbage fly; A. humuti , the hop fly. They are exceedingly prolific, but are kept within bounds by various insects, especially by the Coccinellidæ, or Lady-birds, of which they are the appropriate food. They drop a fluid called honey-dew [HONEY-DEW], which is so grateful to the ants, that the latter, to receive it, tend them like milch cows. The mode of propagating their race is the abnormal one described as ALTERNATION OF GENERATIONS, METAGENESIS, and PARTHENOGENESIS (q.v.). The winged aphides, confe edly perfect insects, bring forth a wingle race, apparently mere larvæ, and which, therefore, it might be thought, would be incapable, while thus immature, of bringing forth young. In certain cases they do it, however, and their offspring are winged, and as perfect as their grand-parents. This alternation of generations, or metagenesis, with its attendant parthenogenesis (or birth from virgins) in every second generation, goes on for nine or ten generations, by which time the season is over. The last aphides of the year are fully formed and winged, and deposit eggs, which are hatched in spring.