So, conversely, modifications in the adult may affect the structure of the larva; but in all cases natural selection will ensure that they shall not be injurious: for if they were so, the species would become extinct.
Natural selection will modify the structure of the young in relation to the parent and of the parent in relation to the young.
In social animals it will adapt the structure of each individual for the benefit of the whole community; if the community profits by the selected change.