Dear Darwin

Many thanks for your 1st. volume which I have just finished reading through with the greatest pleasure and interest;¹ and I have also to thank you for the great tenderness with which you have treated me and my heresies.

On the subject of “sexual selection” & “protection” you do not yet convince me that I am wrong,—but I expect your heaviest artillery will be brought up in your 2nd. vol. & I may have to capitulate. You seem however to have somewhat misunderstood my exact meaning, & I do not think the difference between us is quite so great as you seem to think it. There are a number of passages in which you argue against the view, that the female has, in any large number of cases been “specially modified” for protection,—or that colour has generally been obtained by either sex for purposes of protection.²

But my view is, & I thought I had made it clear, that the female has (in most cases) been simply prevented from acquiring the gay tints of the male (even when there was a tendency for her to inherit it) because it was hurtful;—and, that when protection is not needed, gay colours are so generally acquired by both sexes as to show, that inheritance by both sexes of colour variations is the most usual, when not prevented from acting by nat. selection.³

The colour itself may be acquired either by sexual selection or by other unknown causes.

There are however difficulties in the very wide application you give to sexual selection which at present stagger me, though no one was or is more ready than myself to admit the perfect truth of the principle or the immense importance & great variety of its applications.

Your chapters on “Man” are of intense interest,—but as touching my special heresy not as yet altogether convincing, though of course I fully agree with every word and every argument which goes to prove the “evolution” or “development” of man out of a lower form. My only difficulties are, as to whether you have accounted for every step of the developments by ascertained laws.⁴

Feeling sure that the book will keep up & increase your high reputation & be immensely successful, as it deserves to be,

Believe me Dear Darwin | Yours very faithfully | Alfred R. Wallace

C. Darwin F.R.S.