Upper surface:—fore wings as in _P. Onesimus_, Hew.; hind wings yellowish-white, a broad black border along the anterior, and a narrow one along the posterior margin, two yellowish lunules near the outer angle, anal angle pale yellow, then an oblong black spot with a bluish mark in its upper part, followed by a second (half-obliterated) black spot. Under surface with the same markings; but there are a series of six blue angulated marks upon a black ground, the two intermediate ones being smaller and less distinct. Abdomen yellow; under side black. _Hab._ Dorey (New Guinea) (_Wall._) _Remarks._—This specimen was taken in company with two males, as before mentioned. An insect, described by M. Montrouzier as the female of his _P. Godartii_ (from Woodlark Island), agrees very closely with this, and is no doubt the female of the same species, or a closely allied one which he puts in his list as _P. Ormenus_. The fact, therefore, that this peculiar pale form of female _Papilio_ has been found in five islands, from no one of which is a male insect known which can be mated with it, except those of the _Ormenus_-form (which always occur in the same places), may, in conjunction with the observation already given of the companionship of the two forms, be taken to prove that this is really a case of polymorphism. I believe also it will be found that these extreme departures from the typical form of a species are connected with mimetic resemblances and the safety of the individuals. We have already seen that the extreme forms of _P. Memnon_ ♀ and _P. Pammon_ ♀ respectively resemble other species which from their habits and abundance seem to have some peculiar immunity from danger. In this case also there is a resemblance to quite a different family of butterflies, the Morphidæ. In form, coloration, and general appearance these pale-coloured Papilios resemble species of the genus _Drusilla_; and the same genus is also imitated by other butterflies—one of these, _Melanitis Agondas_ ♀, having been actually confounded with _Drusilla bioculata_ as the same species, so great is the resemblance. This fact of species of several genera imitating the Drusillas would indicate that they have some special immunities which make it advantageous to other insects to be mistaken for them; and their habits confirm this opinion. They have all a very similar style of dress, and fly very slowly, low down in damp woods, often settling on the ground or on rotten wood; and they are exceedingly abundant in individuals. Now these are the general characteristics of all groups which are the subjects of imitation; and we may therefore presume, when we see forms departing widely from the general appearance of their close relations, and resembling closely other groups with which they have no affinity, that what we must call _accidental_ variations have been accumulated and rendered definite by natural selection for the protection and benefit of those forms.