therefore material for natural
selection to act upon, so as ultimately to produce a copy as exact as in
the other cases.

The eastern Papilios allied to Polydorus, Coon, and Philoxenus, form a
natural section of the genus resembling, in many respects, the
AEneas-group of South America, which they may be said to represent in the
East. Like them, they are forest insects, have a low and weak flight,
and in their favourite localities are rather abundant in individuals;
and like them, too, they are the objects of mimicry. We may conclude,
therefore, that they possess some hidden means of protection, which
makes it useful to other insects to be mistaken for them.

The Papilios which resemble them belong to a very distinct section of
the genus, in which the sexes differ greatly; and it is those females
only which differ most from the males, and which have already been
alluded to as exhibiting instances of dimorphism, which resemble species
of the other group.

The resemblance of P. Romulus to P. Hector is, in some specimens, very
considerable, and has led to the two species being placed following each
other in the British Museum Catalogues and by Mr. E. Doubleday. I have
shown, however, that P. Romulus is probably a dimorphic form of the
female P. Pammon, and belongs to a distinct section of the genus.

The next pair, Papilio Theseus, and P. Antiphus, have been united as one
species both by De Haan and in the British Museum Catalogues. The
ordinary variety of P. Theseus found in Java almost as nearly resembles
P. Diphilus, inhabiting the same country. The most interesting case,
however, is the extreme female form of P. Memnon (figured by Cramer
under the name of P. Achates), which has acquired the general form and
markings of P. Coon, an insect which differs from the ordinary male P.
Memnon, as much as any two species which can be chosen in this extensive
and highly varied genus; and, as if to show that this resemblance is not
accidental, but is the result of law, when in India we find a species
closely allied to P. Coon, but with red instead of yellow spots (P.
Doubledayi), the corresponding variety of P. Androgeus (P. Achates,
Cramer, 182, A, B,) has acquired exactly the same peculiarity of having
red spots instead of yellow. Lastly, in the island of Timor, the female
of P. Oenomaus (a species allied to P. Memnon) resembles so closely P.
Liris (one of the Polydorus-group), that the two, which were often seen
flying toget