THE HISTORY OF THE ROSE APHIS, OR PLANT LOUSE.

Wairarapa Daily Times, Volume XVI, Issue 2038, 10 July 1885, Page 2

THE HISTORY OF THE ROSE APHIS, OR PLANT LOUSE.

In the spring, the eggs of last year's crop, which have been laid by the mothers in nooks and crannies out of reach of the frost, are quickened into life by the first return of warm weather, and hatch out their brood of insects, All this broud consists of imperfect females, without a single male among them; and they all fasten at once upon the young buds of their native bush, where they pass a sluggish and uneventful existence in sucking up the juice from the veins on the 0110 hand, and secreting honeydew upon the other. Four times thoy moult their skins, those moults being in some respects analogous-to the metamorphosis of the caterpillar into chrysalis and butterfly, Afterthefourthmoulttheyoung aphides attain maturity; and. then they give orgin, parthonogenetically, to a second brood, also of iiuporfcct families, all produced without &ny fatlurs. This brood brings forth in like maimer a third generation, as' soxual as before ; and tlio sarao process is repeated without intermission as long as tliS warm weather lasts. In oacli case the young simply, bud oijfc from the ovaties'of tlio mothers, exactly as new crops of leaves bud out from tho rose,branch on' which they grow. Eleven generations have, thus been observed to follow one another rapidly in a single summer-; ai& indeed, by keeping the aphides in a warm room, one may evon make them continue their reproduction in this purely vegetable fashion for as many as four years running. But as soon as the cold weather begins to set in, perfect male and female insects are produced by the last swann of tic mothers; and these true females, after being fertilised, lay tho eggs which remain through the winter, and from which the next summer's broods have to begin again the wonderful cycle. Thus, only one generation of aphides, out of ten or eleven, consists of true males or females; all the rest are false females, producing young by a process of budding. 'Longman's Magazine,'