t that the sounds and vocal organs of some
males are used only for challenging, but I doubt whether this applies to
the musical notes of Hylobates or to the howling (I judge chiefly from
Rengger) of the American monkeys. No account that I have seen of the
stridulation of male insects shows that it is a challenge. All those who
have attended to birds consider their song as a charm to the females and
not as a challenge. As the males in most cases search for the females I
do not see how their odoriferous organs will aid them in finding the
females. But it is foolish in me to go on writing, for I believe I have
said most of this in my book: anyhow, I well remember thinking over it.
The "belling" of male stags, if I remember rightly, is a challenge, and
so I daresay is the roaring of the lion during the breeding season.

I will just add in reference to your former letter that I fully admit
that with birds the fighting of the males co-operates with their charms;
and I remember quoting Bartlett that gaudy colouring in the males is
almost invariably concomitant with pugnacity. But, thank Heaven, what
little more I can do in science will be confined to observation on
simple points. However much I may have blundered, I have done my best,
and that is my constant comfort.--Most truly yours,

C. DARWIN.

* * * * *

_Waldron Edge, Duppas Hill, Croydon. September 14, 1878._

Dear Darwin,--An appointment is soon to be made of someone to have the
superintendence of Epping Forest under the new Act, and as it is a post
which of all others I should like I am trying very hard to get up
interest enough to secure it.

One of the means is the enclosed memorial, which has been already signed
by Sir J. Hooker and Sir J. Lubbock, and to which I feel sure you will
add your name, which I expect has weight "even in the City."

In want of anything better to do I have been grinding away at a book on
the Geography of Australia for Stanford for the last six months.

Hoping you are in good health, and with my best compliments to Mrs.
Darwin and the rest of your family, believe me yours very faithfully,

ALFRED R. WALLACE

* * * * *

_Down, Beckenham, Kent. September 16, 1878._

My dear Wallace,--I return the paper signed, and most heartily wish that
you may be successful, not only for your own sake, but for that of
Natural Science, as you would then have more time for new research