., pages 386-401, where
Dr. Wallace's observations are quoted.), of Colchester, about the
proportional numbers of the two sexes in Bombyx; and in this note,
apropos to an incidental remark of mine, he stoutly maintains that
female lepidoptera never notice the colours or appearance of the male,
but always receive the first male which comes; and this appears very
probable. He says he has often seen fine females receive old battered
and pale-tinted males. I shall have to admit this very great objection
to sexual selection in insects. His observations no doubt apply to
English lepidoptera, in most of which the sexes are alike. The brimstone
or orange-tip would be good to observe in this respect, but it is
hopelessly difficult. I think I have often seen several males following
one female; and what decides which male shall succeed? How is this about
several males; is it not so?

LETTER 435. TO J. JENNER WEIR. 6, Queen Anne Street, Cavendish Square,
W. [March 6th, 1868].

I have come here for a few weeks, for a little change and rest. Just as
I was leaving home I received your first note, and yesterday a second;
and both are most interesting and valuable to me. That is a very curious
observation about the goldfinch's beak (435/1. "Descent of Man,"
Edition I., Volume I., page 39. Mr. Weir is quoted as saying that the
birdcatchers can distinguish the males of the goldfinch, Carduelis
elegans, by their "slightly longer beaks."), but one would hardly like
to trust it without measurement or comparison of the beaks of several
male and female birds; for I do not understand that you yourself assert
that the beak of the male is sensibly longer than that of the female. If
you come across any acute birdcatchers (I do not mean to ask you to
go after them), I wish you would ask what is their impression on the
relative numbers of the sexes of any birds which they habitually catch,
and whether some years males are more numerous and some years females.
I see that I must trust to analogy (an unsafe support) for sexual
selection in regard to colour in butterflies. You speak of the brimstone
butterfly and genus Edusa (435/2. Colias Edusa.) (I forget what this is,
and have no books here, unless it is Colias) not opening their wings.
In one of my notes to Mr. Stainton I asked him (but he could or did not
answer) whether butterflies such as the Fritillaries, with wings bright
beneath and above, opened and shut their wings more than Vanessae, mos