nais
sobrina, from the same country, just as Papilio Marcareus resembles
Danais Aglaia in Malacca, and (according to Dr. Horsfield's figure)
still more closely in Java. The Indian Papilio Agestor closely imitates
Danais Tytia, which has quite a different style of colouring from the
preceding; and the extraordinary Papilio Idaeoides from the Philippine
Islands, must, when on the wing, perfectly resemble the Hestia Leuconoe
of the same region, as also does the Papilio Delessertii imitate the
Ideopsis daos from Penang. Now in every one of these cases the Papilios
are very scarce, while the Danaidae which they resemble are exceedingly
abundant--most of them swarming so as to be a positive nuisance to the
collecting entomologist by continually hovering before him when he is in
search of newer and more varied captures. Every garden, every roadside,
the suburbs of every village are full of them, indicating very clearly
that their life is an easy one, and that they are free from persecution
by the foes which keep down the population of less favoured races. This
superabundant population has been shown by Mr. Bates to be a general
characteristic of all American groups and species which are objects of
mimicry; and it is interesting to find his observations confirmed by
examples on the other side of the globe.

The remarkable genus Drusilla, a group of pale-coloured butterflies,
more or less adorned with ocellate spots, is also the object of mimicry
by three distinct genera (Melanitis, Hyantis, and Papilio). These
insects, like the Danaidae, are abundant in individuals, have a very
weak and slow flight, and do not seek concealment, or appear to have any
means of protection from insectivorous creatures. It is natural to
conclude, therefore, that they have some hidden property which saves
them from attack; and it is easy to see that when any other insects, by
what we call accidental variation, come more or less remotely to
resemble them, the latter will share to some extent in their immunity.
An extraordinary dimorphic form of the female of Papilio Ormenus has
come to resemble the Drusillas sufficiently to be taken for one of that
group at a little distance; and it is curious that I captured one of
these Papilios in the Aru Islands hovering along the ground, and
settling on it occasionally, just as it is the habit of the Drusillas to
do. The resemblance in this case is only general; but this form of
Papilio varies much, and there is