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The Descent of Man

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the female has been effected apparently at a<br />

remote period, the male having subsequently<br />

undergone great changes, without transferring<br />

to the female any <strong>of</strong> his later-gained characters.<br />

For instance, the female and the young <strong>of</strong> the<br />

black-grouse (Tetrao tetrix) resemble pretty<br />

closely both sexes and the young <strong>of</strong> the redgrouse<br />

(T. scoticus); and we may consequently<br />

infer that the black-grouse is descended from<br />

some ancient species, <strong>of</strong> which both sexes were<br />

coloured in nearly the same manner as the redgrouse.<br />

As both sexes <strong>of</strong> this latter species are<br />

more distinctly barred during the breedingseason<br />

than at any other time, and as the male<br />

differs slightly from the female in his more<br />

strongly- pronounced red and brown tints (10.<br />

Macgillivray, 'History <strong>of</strong> British Birds,' vol. i.<br />

pp. 172-174.), we may conclude that his plumage<br />

has been influenced by sexual selection, at<br />

least to a certain extent. If so, we may further<br />

infer that nearly similar plumage <strong>of</strong> the female<br />

black-grouse was similarly produced at some

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