Page:The Effect of External Influences upon Development.djvu/40

36 p. 62). The degree in which the maturation of the eggs of insects depends on their food is also shown by my experiments with flies, which when poorly fed after reaching the imago-state produced no eggs at all, the ovaries remaining in the unripe condition in which they are always found in the young image, even when there has been abundant food for the larva.

The facts, therefore, support neither the idea that the degeneration of the ovary of the workers is a direct consequence of poverty of nutrition, nor the view that an increased sensitiveness of the ovary to the influence of nourishment is here concerned. But they do show that poor nourishment acts as the stimulus for the latent primary constituents for the workers in the germ-plasm;—not only for those of the ovary, but also for those of all characters by which the worker is distinguished from the queen.

It might at first perhaps appear peculiar that one and the same egg should contain double primary constituents of numerous parts of the body; but we need not be surprised at this if we reflect that double primary constituents of many parts of the body—namely those for the male and female—must certainly be contained in the eggs of almost all animals. In a few cases these constituents are even distributed to two different kinds of eggs which differ in size: take the case, for instance, of rotifers and of the Phylloxera, in which it is consequently beyond doubt that each sex has its own