8 MR. A. R. WALLACE ON THE PAPILIONID^ 



these two groups of Papilio, and I am disposed to believe that we have here a case of 

 mimicry, brought about by the same causes which Mr. Bates has so well explained in his 

 account of Heliconidop, and which thus led to the singular exuberance of polymorphic 

 forms in this and allied groups of the genus Papilio. I shall have to devote a section of 

 my paper to the consideration of this subject. 



The third example of polymorphism I have to bring forward is Papilio Onnemis, 

 Guer., which is closely allied to the well-known P. E)'echthei(s, Don., of Australia. The 

 most common form of the female also resembles that of P. Erechtheus ; but a totally 

 different-looking insect was found by myself in the Aru Islands, and figui-ed by Mr. 

 Hewitson imder the name of P. Onesimus, which subsequent observation has convinced 

 me is a second form of the female of P. Ormenus. Comparison of this with Boisduval's 

 description of P. Amanga, a specimen of which from New Guinea is in the Paris 

 Museum, shows the latter to be a closely similar form ; and two other specimens were 

 obtained by myself, one in the island of Goram and the other in Waigiou, all evidently 

 local modifications of the same form. In each of these localities males and ordinary 

 females of P. Ormenus were also found. So far there is no CAridence that these li^ht- 

 coloured insects are not females of a distinct species, the males of which have not been 

 discovered. But two facts have con-vinced me this is not the case. At Dorey, in New 

 Guinea, where males and ordinary females closely allied to P. Ormenus occur (but wliich 

 seem to me worthy of being separated as a distinct species), I found one of these light- 

 coloured females closely followed in her flight by three males, exactly in the same manner 

 as occurs (and, I believe, occurs only) with the sexes of the same species. After watching 

 them a considerable time, I captured the whole of them, and became satisfied that I 

 had discovered the true relations of this anomalous form. The next year I had corro- 

 borative proof of the correctness of this opinion by the discovery in the island of Bat- 

 cliian of a new species allied to P. Ormenus, all the females of which, either seen or 

 cajitared by me, were of one form, and much more closely resembling the abnormal 

 light-coloui*ed females of P. Ormenus and P. Pandion than the ordinary specimens of 

 that sex. Every naturalist will, I think, agree that this is strongly confirmative of the 

 supposition that both forms of female are of one species ; and when we consider, further, 

 that in four separate islands, in each of which I resided for several months, the two forms 

 of female were obtained and only one form of male ever seen, and that about the same 

 time M. Montrouzier in "Woodlark Island, at the other extremity of New Guinea (where 

 he resided several years, and must have obtained all the large Lepidoptera of the island), 

 obtained females closely resembling mine, which, in despair at finding no appropriate 

 partners for them, he mates with a widely different species, — it becomes, I think, 

 sufficiently evident that this is another case of polymorphism of the same nature as 

 those abeady pointed out in P. Pammon and P. Ilemnon. This species, however, is 

 not only dimorphic, but trimorphic ; for, in the island of Waigiou, I obtained a third 

 female quite distinct from either of the others, and in some degree intermediate between 

 the ordinary female and the male. The specimen is particularly interesting to those 

 who believe, with Mr. Darwin, that extreme difference of the sexes has been gradually 

 produced by what he terms sexual selection, since it may be supposed to exhibit one of 



