I hope this will reach you before you leave.—­Believe me yours very faithfully,

ALFRED R. WALLACE.

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Hurstpierpoint.  March 8, 1868.

Dear Darwin,—­I am very sorry your letter came back here while I was going to town, or I should have been very pleased to have seen you.

Trimen’s paper at the Linnean was a very good one, but the only opponents were Andrew Murray and B. Seeman.  The former talked utter nonsense about the “harmony of nature” produced by “polarisation,” alike in “rocks, plants and animals,” etc. etc. etc.  And Seeman objected that there was mimicry among plants, and that our theory would not explain it.

Lubbock answered them both in his best manner.

Pray take your rest, and put my last notes by till you return to Down, or let your son discover the fallacies in them.

Would you like to see the specimens of pupae of butterflies whose colours have changed in accordance with the colour of the surrounding objects?  They are very curious, and Mr. T.W.  Wood, who bred them, would, I am sure, be delighted to bring them to show you.  His address is 89 Stanhope Street, Hampstead Road, N.W.—­Believe me yours very faithfully,

ALFRED R. WALLACE.

Darwin had already written a short note to Wallace expressing a general dissent from his views.

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4 Chester Place, Regent’s Park, N.W.  March 17, 1868.

My dear Wallace,—­Many thanks about Pieridae.  I have no photographs up here, but will remember to send one from Down.  Should you care to have a large one, of treble or quadruple common size, I will with pleasure send you one under glass cover, to any address you like in London, either now or hereafter.  I grieve to say we shall not be here on April 2nd, as we return home on the 31st.  In summer I hope that Mrs. Wallace and yourself will pay us a visit at Down, soon after you return to London; for I am sure you will allow me the freedom of an invalid.

My paper to-morrow at the Linnean Society is simply to prove, alas! that primrose and cowslip are as good species as any in the world, and that there is no trustworthy evidence of one producing the other.  The only interesting point is the frequency of the production of natural hybrids, i.e. oxlips, and the existence of one kind of oxlip which constitutes a third good and distinct species.  I do not suppose that I shall be able to attend the Linnean Society to-morrow.

I have been working hard in collecting facts on sexual selection every morning in London, and have done a good deal; but the subject grows more and more complex, and in many respects more difficult and doubtful.  I have had grand success this morning in tracing gradational steps by which the peacock tail has been developed:  I quite feel as if I had seen a long line of its progenitors.