200 SUMATRA. [ c h a p . v m .
supposed to form several distinct species. They may be
divided into two groups—those which resemble the male
in shape, and those which differ entirely from him in the
DIFFEREN T FEMALES OF PA P I LI O' M'EMNON_
outline of the wings. The first vary much in colour,
being often nearly white with dusky yellow and red
markings, but such differences often occur in butterflies.
The second group are much more extraordinary, and would
CHAP. vm.] CURIOUS BUTTERFLIES.
never be supposed to be the same insect, since the hind
wings are lengthened out into large spoon-shaped tails, no
rudiment of which is ever to be perceived in the males or
in the ordinary form of females. These tailed females are
never of the dark and blue-glased tints which prevail in
PAPIL IO COON.
the male and often occur in the females of the same form,
but are invariably ornamented with stripes and patches of
white or buff, occupying the larger part of the surface of
the hind wings. This peculiarity of colouring led me to
discover that this extraordinary female closely resembles
(when flying) another butterfly of the same genus but of a
different group (Papilio coon); and that we have here a
case of mimicry similar to those so well illustrated and