Origin of Species Variorum

from their parents to any conceivable extent. Differences in the larvæ might, also, become correlated with successive stages of development; so that the larvæ in the first stage, might come to differ greatly from the larvæ in the second stage, as is the case with so many animals. The adult might also become fitted for sites or habits, in which the organs of locomotion or of the senses, &c., would be useless; and in this case the final metamorphosis would be said to be retrograde.

From the remarks above made we can see how by alterations of structure in the young, in conformity with altered habits of life, together with inheritance at corresponding ages, the metamorphoses of certain animals might first have been acquired, and subsequently transmitted to numerous modified descendants. ↑ Fritz Müller, who has recently discussed this whole subject with much ability, goes so far as to believe that the progenitor of all insects probably resembled an adult insect, and that the caterpillar or maggot, and cocoon or pupal stages, have subsequently been acquired; but from this view many naturalists, for instance Sir J. Lubbock, who has likewise recently discussed this subject, would, it is probable, dissent. That certain unusual stages in the metamorphoses of insects have arisen from adaptations to peculiar habits of life can hardly be doubted: thus the first larval form of a certain beetle, the Sitaris, as described by M. Fabre, is a minute, active insect, furnished with six legs, two long antennæ, and four eyes. These larvæ are hatched in the nest of a bee; and when the male-bees emerge in the spring from their burrows, which they do before the females, the larvæ spring on them, and afterwards take an early and natural opportunity of crawling on to the female-bees. When the latter lay their eggs, one in each cell, on the surface of the contained honey, the larva leaps on the egg and