lours of
females, the more difficulty I find in accepting them, and as you are
now working at the subject I hope it will not interrupt you to hear
"counsel on the other side."

I have a "general" and a "special" argument to submit.

1. Female birds and insects are generally exposed to more danger than
the male, and in the case of insects their existence is necessary for a
longer period.

2. They therefore require in some way or other a special balance of
protection.

3. Now, if the male and female were distinct species, with different
habits and organisations, you would, I think, at once admit that a
difference of colour serving to make that one less conspicuous which
evidently required more protection than the other had been acquired by
Natural Selection.

4. But you admit that variations appearing in one sex are transmitted
(often) to that sex only: there is therefore nothing to prevent Natural
Selection acting on the two sexes as if they were two species.

5. Your objection that the same protection would to a certain extent be
useful to the male, seems to me utterly unsound, and directly opposed to
your own doctrine so convincingly urged in the "Origin," "_that Natural
Selection never can improve an animal beyond its needs_." So that
admitting abundant variation of colour in the male, it is impossible
that he can be brought by Natural Selection to resemble the female
(unless _her_ variations are always transmitted to _him_), because the
_difference_ of their colours is to balance the _difference_ in their
organisations and habits, and Natural Selection cannot give to the male
_more_ than is needed to effect that balance.

6. The fact that in almost all protected groups the females perfectly
resemble the males shows, I think, a tendency to transference of colour
from one sex to the other when this tendency is not injurious.

Or perhaps the _protection_ is acquired because this tendency exists. I
admit therefore in the case of concealed nests they [habits] may have
been acquired for protection.

Now for the special case.

7. In the very weak-flying Leptalis both sexes mimic Heliconidae.

8. In the much more powerful Papilio, Pieris, and Diadema it is
generally the _female only_ that mimics Danaida.

9. In these cases the females often acquire more bright and varied
colours than the male. Sometimes, as in _Pieris pyrrha_, conspicuously
so.

10. No single case is known of a male Papilio, Pieris, Diadema