ter
point. But I cannot yet persuade myself that females _alone_ have often
been modified for protection. Should you grudge the trouble briefly to
tell me whether you believe that the plainer head and less bright
_colours_ of [female symbol][73] chaffinch, the less red on the head and
less clean colours of [female symbol] goldfinch, the much less red on
breast of [female symbol] bullfinch, the paler crest of goldencrest
wren, etc., have been acquired by them for protection? I cannot think
so; any more than I can that the considerable differences between
[female symbol] and [male symbol] house-sparrow, or much greater
brightness of [male symbol] _Parus caeruleus_ (both of which build under
cover) than of [female symbol] Parus are related to protection. I even
misdoubt much whether the less blackness of blackbird is for protection.

Again, can you give me reason for believing that the merest differences
between female pheasants, the female _Gallus bankiva_, the female of
black grouse, the pea-hen, female partridge, have all special reference
to protection under slightly different conditions? I of course admit
that 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 fishes--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 symbol] finches and
Gallinaceae would suffice.--Believe me, my dear Wallace, yours very
sincerely,

CH. DARWIN.

* * * * *

_9 St. Mark's Crescent, S.W. September 27, 1868._

Dear Darwin,--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 gradatio