rne Grove.

I suppose you will now be going on with your book on Sexual Selection
and Man, by way of relaxation! It is a glorious subject, but will
require delicate handling,--Yours very faithfully,

ALFRED R. WALLACE.

* * * * *

_10 Duchess Street, W. February 7, 1868._

Dear Darwin,--I have to thank you for signing the Memorial as to the
East London Museum, and also for your kindness in sending me a copy of
your great book, which I have only just received. I shall take it down
in the country with me next week, and enjoy every line at my leisure.

Allow me also to congratulate you on the splendid position obtained by
your second son at Cambridge.

You will perhaps be glad to hear that I have been for some time
hammering away at my Travels, but I fear I shall make a mess of it. I
shall leave most of the Natural History generalisation, etc., for
another work, as if I wait to incorporate all, I may wait for
years.--Hoping you are quite well, believe me yours very faithfully,

ALFRED R. WALLACE.

* * * * *

_Down, Bromley, Kent, S.E. February 22, [1868?]._

My dear Wallace,--I am hard at work on sexual selection and am driven
half mad by the number of collateral points which require investigation,
such as the relative numbers of the two sexes, and especially on
polygamy. Can you aid me with respect to birds which have strongly
marked secondary sexual characters, such as birds of paradise,
humming-birds, the rupicola or rock-thrush, or any other such cases?
Many gallinaceous birds certainly are polygamous. I suppose that birds
may be known not to be polygamous if they are seen during the whole
breeding season to associate in pairs, or if the male incubates, or aids
in feeding the young. Will you have the kindness to turn this in your
mind? but it is a shame to trouble you now that, as I am _heartily_ glad
to hear, you are at work on your Malayan Travels. I am fearfully puzzled
how far to extend your protective views with respect to the females in
various classes. The more I work, the more important sexual selection
apparently comes out.

Can butterflies be polygamous?--i.e. will one male impregnate more than
one female?

Forgive me troubling you, and I daresay I shall have to ask your
forgiveness again, and believe me, my dear Wallace, yours most
sincerely,

CH. DARWIN.

P.S.--Baker has had the kindness to set the Entomological Society
discu