Collier's New Encyclopedia

A complete general encyclopedia of 1921 — the world as it was understood just after the Great War, from Aachen to Zwingli, across twelve volumes and six thousand pages.

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Parthenogenesis

in biology, a term introduced by Professor Owen, who calls it also metagenesis. It signifies generation by means of an unimpregnated insect, which, moreover, is immature, not having yet passed beyond the larval state. Example, the genus Aphis.

The winged aphides deposit eggs which produce imperfect wingless offspring, apparently mere larvæ. These larvæ, however, in some abnormal way, reproduce their species. By the time the process has gone on for 9 or 10 generations, the season is about closing, and the last brood of the larval aphides produce fully formed and winged specimens of the species, depositing eggs which are hatched in the following spring.

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