they are all protected by dull colours, derived, as I think, from some
dull-ground progenitor; and I account partly for their difference by
partial transference of colour from the male, and by other means too long
to specify; but I earnestly wish to see reason to believe that each is
specially adapted for concealment to its environment.

I grieve to differ from you, and it actually terrifies me and makes me
constantly distrust myself. I fear we shall never quite understand each
other. I value the cases of bright-coloured, incubating male fisher, and
brilliant female butterflies, solely as showing that one sex may be made
brilliant without any necessary transference of beauty to the other sex;
for in these cases I cannot suppose that beauty in the other sex was
checked by selection.

I fear this letter will trouble you to read it. A very short answer about
your belief in regard to the female finches and Gallinaceae would suffice.


LETTER 450. A.R. WALLACE TO CHARLES DARWIN.
9, St. Mark's Crescent, N.W., September 27th, 1868.

Your view seems to be that variations occurring in one sex are transmitted
either to that sex exclusively or to both sexes equally, or more rarely
partially transferred. But we have every gradation of sexual colours, from
total dissimilarity to perfect identity. If this is explained solely by
the laws of inheritance, then the colours of one or other sex will be
always (in relation to the environment) a matter of chance. I cannot think
this. I think selection more powerful than laws of inheritance, of which
it makes use, as shown by cases of two, three or four forms of female
butterflies, all of which have, I have little doubt, been specialised for