Origin of Species Variorum

Comparison with 1869

peculiar manner as does our British thrush: how it is that the male wrens (Troglodytes) of North America, build "cock-nests," to roost in, like the males in a hole in a tree, with only a small hole left in the plaster through which the males feed them and the young when hatched: how it is that the male wrens (Troglodytes) of North America build "cock-nests," to roost in, like the males of our Kitty-wrens,— a habit wholly unlike that of any other known bird. Finally, it may not be a logical deduction, but to my imagination it is far more satisfactory to look at such instincts as the young cuckoo ejecting its foster-brothers,— ants making slaves,— the larvæ of ichneumonidæ feeding within the live bodies of caterpillars,— not as specially endowed or created instincts, but as small consequences of one general law, leading to the advancement of all organic beings,— namely, multiply, vary, let the strongest live and the weakest die.

peculiar manner as does our British thrush: how it is that the Hornbills of Africa and India have the same extraordinary instinct of plastering up and imprisoning the females in a hole in a tree, with only a small hole left in the plaster through which the males feed them and their young when hatched: how it is that the male wrens (Troglodytes) of North America, build "cock-nests," to roost in, like the males of our distinct Kitty-wrens,— a habit wholly unlike that of any other known bird. Finally, it may not be a logical deduction, but to my imagination it is far more satisfactory to look at such instincts as the young cuckoo ejecting its foster-brothers,— ants making slaves,— the larvæ of ichneumonidæ feeding within the live bodies of caterpillars,— not as specially endowed or created instincts, but as small consequences of one general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die.