Origin of Species Variorum

Comparison with 1872

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, animals might come to pass through stages of development, perfectly distinct from the primordial condition of their adult progenitors. Most of our best authorities are now convinced that the various larval and pupal stages of insects have thus been acquired through adaptation, and not through inheritance from some ancient form. The curious case of Sitaris— a beetle which passes through certain unusual stages of development— will illustrate how this might occur. The first larval form is described by M. Fabre, as an active, minute insect, furnished with six legs, two long antennæ, and four eyes. These larvæ are hatched in the nests of bees; and when the male-bees emerge from their burrows, in the spring, which they do before the females, the larvæ spring on them, and afterwards crawl on to the females whilst paired with the males. As soon as the female bee deposits her eggs on the surface of the honey stored in the cells, the larvæ of the Sitaris leap on the eggs and devour them. Afterwards they undergo a complete change; their eyes disappear; their legs and antennæ become rudimentary, and they feed on honey; so that they now more closely resemble the ordinary larvæ of insects; ultimately they undergo a further transformation, and finally emerge as the perfect beetle. ↑ Now, if an insect, undergoing transformations like those of the Sitaris, had been the progenitor of the whole great class of insects, the course of development

From the remarks just made we can see how by changes of structure in the young, in conformity with changed habits of life, together with inheritance at corresponding ages, animals in certain cases might come to pass through stages of development, perfectly distinct from their primordial, adult condition. ↑ Fritz Müller, who has recently discussed this .. subject with much ability, ... believes that the progenitor of all insects .. resembled an adult insect, and that the caterpillar or maggot stages, as well as the 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 been acquired through adaptation to peculiar habits of life, there can hardly be a doubt: thus the first larval form of a certain beetle, the Sitaris, as described by M. Fabre, is an active, minute insect, furnished with six legs, two long antennæ, and four eyes. These larvæ are hatched in the nests of .. bees; and when the male-bees emerge ... from their burrows in the spring, which they do before the females, the larvæ spring on them, and afterwards crawl on the females whilst paired with the males. As soon as the females lay their eggs ... on the surface of the .. honey stored in their cells, the larvæ of the Sitaris leap on the eggs and devour them. Afterwards these larvæ undergo a complete change; their eyes disappear; their legs and antennæ become rudimentary, and they feed on honey; so that they now more closely resemble the ordinary larvæ of insects; ultimately they undergo a further transformation, and finally emerge as the perfect beetle. Now, if an insect, undergoing transformations like those of the Sitaris, were to become the progenitor of a whole new class of insects, their course of develop- ment