. Circular. Insects. Fig. 2.—The spring grain-aphis {Toxoptera graminum) : a, wingless female; b, larva; c, pupa. Much enlarged (original). I Young develop to adults and themselves begin to reproduce within the . space of a week, so that in favorable weather several generations may | be fully represented on the same plant by young of all ages and winged | and wingless females. RAPIDITY OF INCREASE. In experiments with a winged female in April, in Indiana, the writer obtained 37 offspring within the period of eighteen days, and at the i end of this time some of her firstborn were themselves gra
. Circular. Insects. Fig. 2.—The spring grain-aphis {Toxoptera graminum) : a, wingless female; b, larva; c, pupa. Much enlarged (original). I Young develop to adults and themselves begin to reproduce within the . space of a week, so that in favorable weather several generations may | be fully represented on the same plant by young of all ages and winged | and wingless females. RAPIDITY OF INCREASE. In experiments with a winged female in April, in Indiana, the writer obtained 37 offspring within the period of eighteen days, and at the i end of this time some of her firstborn were themselves grandmothers. ' From the writer's experience with allied species it is probable that the 1 wingless female is much more prolific than the winged female, so that it would be entirely within reason to suppose that a wingless mother - would be capable of producing at least double the number of young \ mentioned above within a slightly more extended period of time. It will thus be seen that within a brief period, under favorable circum-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Bureau of Entomology. Washington, Govt. print. off.
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectinsects
