My dear Wallace,—­I must have expressed myself atrociously; I meant to say exactly the reverse of what you have understood.  F. Jenkin argued in the North British Review[76] against single variations ever being perpetuated, and has convinced me, though not in quite so broad a manner as here put.  I always thought individual differences more important, but I was blind and thought that single variations might be preserved much oftener than I now see is possible or probable.  I mentioned this in my former note merely because I believed that you had come to similar conclusions, and I like much to be in accord with you.  I believe I was mainly deceived by single variations offering such simple illustrations, as when man selects.

We heartily congratulate you on the birth of your little
daughter.—­Yours very sincerely,

C. DARWIN.

* * * * *

Down, Bromley, Kent, S.E.  March 5, 1869.

My dear Wallace,—­I was delighted at receiving your book[77] this morning.  The whole appearance and the illustrations with which it [is] so profusely ornamented are quite beautiful.  Blessings on you and your publisher for having the pages cut and gilded.

As for the dedication, putting quite aside how far I deserve what you say, it seems to me decidedly the best expressed dedication which I have ever met.

The reading will probably last me a month, for I dare not have it read aloud, as I know that it will set me thinking.

I see that many points will interest me greatly.  When I have finished, if I have anything particular to say, I will write again.  Accept my cordial thanks.  The dedication is a thing for my children’s children to be proud of.—­Yours most sincerely,

CH.  DARWIN.

* * * * *

9 St. Mark’s Crescent, N.W.  March 10, 1869.

Dear Darwin,—­Thanks for your kind note.  I could not persuade Mr. Macmillan to cut more than twenty-five copies for my own friends, and he even seemed to think this a sign of most strange and barbarous taste.

Mr. Weir’s paper on the kinds of larvae, etc., eaten or rejected by insectivorous birds was read at the last meeting of the Entomological Society and was most interesting and satisfactory.  His observations and experiments, so far as they have yet gone, confirm in every instance my hypothetical explanation of the colours of caterpillars.  He finds that all nocturnal-feeding obscure-coloured caterpillars, all green and brown and mimicking caterpillars, are greedily eaten by almost every insectivorous bird.  On the other hand, every gaily coloured, spotted or banded species, which never conceal themselves, and all spiny and hairy kinds, are invariably rejected, either without or after trial.  He has also come to the curious and rather unexpected conclusion, that hairy and spiny caterpillars are not protected by their hairs, but by their nauseous taste, the hairs being merely an external mark of their uneatableness, like the gay colours of others.  He deduces this from two kinds of facts:  (1) that very young caterpillars before the hairs are developed are equally rejected, and (2) that in many cases the smooth pupae and even the perfect insects of the same species are equally rejected.