In some cases we might easily put down to disuse modifications of structure which are wholly, or mainly due to natural selection.

在某些情况下， 我们可能很容易将完全或主要归因于自然选择的结构修改归结为弃用。

It appears that I formerly underrated the frequency and value of these latter forms of variation, as leading to permanent modifications of structure independently of natural selection.

看来我以前低估了后一种变异形式的频率和价值，因为它们会导致独立于自然选择的结构永久性修改。

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.

但是对于工作的蚂蚁， 我们有一种昆虫与其父母有很大的不同， 但绝对不育；因此，它永远不可能将连续获得的结构或本能的改变传递给它的后代。