confined to one sex, as will hereafter be more fully explained. The
white female of the Cycnia resembles the very common Spilosoma
menthrasti, both sexes of which are white; and Mr. Stainton observed
that this latter moth was rejected with utter disgust by a whole brood
of young turkeys, which were fond of eating other moths; so that if the
Cycnia was commonly mistaken by British birds for the Spilosoma, it
would escape being devoured, and its white deceptive colour would thus
be highly beneficial.), and these belong to groups which generally fly
about during the afternoon. On the other hand, in many genera, as Mr.
Stainton informs me, the males have the hind-wings whiter than those of
the female of which fact Agrotis exclamationis offers a good instance.
In the Ghost Moth (Hepialus humuli) the difference is more strongly
marked; the males being white, and the females yellow with darker
markings. (21. It is remarkable, that in the Shetland Islands the male
of this moth, instead of differing widely from the female, frequently
resembles her closely in colour (see Mr. MacLachlan, Transactions,
Entomological Society, vol. ii. 1866, p. 459). Mr. G. Fraser suggests
( Nature, April 1871, p. 489) that at the season of the year when the
ghost-moth appears in these northern islands, the whiteness of the
males would not be needed to render them visible to the females in the
twilight night.) It is probable that in these cases the males are thus
rendered more conspicuous, and more easily seen by the females whilst
flying about in the dusk.
From the several foregoing facts it is impossible to admit that the
brilliant colours of butterflies, and of some few moths, have commonly
been acquired for the sake of protection. We have seen that their
colours and elegant patterns are arranged and exhibited as if for
display. Hence I am led to believe that the females prefer or are most
excited by the more brilliant males; for on any other supposition the
males would, as far as we can see, be ornamented to no purpose. We know
that ants and certain Lamellicorn beetles are capable of feeling an
attachment for each other, and that ants recognise their fellows after
an interval of several months. Hence there is no abstract improbability
in the Lepidoptera, which probably stand nearly or quite as high in the
scale as these insects, having sufficient mental capacity to admire
bright colours. They certainly discover flowers by colour. The
Humming-bird Sphinx may often be seen to swoop down from a distance on
a bunch of flowers in the midst of green foliage; and I have been
assured by two persons abroad, that these moths repeatedly visit
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