Note 162 — Chapter XI · THE WRITING OF THE 'ORIGIN OF SPECIES.'
Reading edition
Origin of Species, 6th edition, vol. ii. p. 357. "But with the working ant we have an insect differing greatly from its parents, yet absolutely sterile, so that it could never have transmitted successively acquired modifications of structure or instinct to its progeny. It may well be asked how is it possible to reconcile this case with the theory of natural selection?"