Phenomena of Variation and Geographical Didribution. 171 



correctness of this opinion by the discovery in the island of Batchian 

 of a new species allied to F. Onnenus, all the females of which, either 

 seen or captured by me, wei-e of one form, and much more closely re- 

 sembling tlie abnormal light-colored females of F. Ormenns and F. 

 Fandion, 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 w^ere obtained, and only one 

 foi'm of male ever seen, and that about the same time M. INIontrouzier 

 in Woodlark Island, at the other extremity of New Guinea (where he 

 resided several years, and must have obtained all the large Lepidop- 

 tera 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, sufiiciently evident that this 

 is another case of polymorphism of the same nature as those already 

 pointed out in F. Fammon and F. Memnon. This species, however, is 

 not only dimorphic, but trimorphic ; for, in the island of Waigiou, I ob- 

 tained 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 pro- 

 duced by what he terms sexual selection, since it may be supposed to 

 exhibit one of the intermediate steps in that process which has been 

 accidentally preserved in company with its more favored rivals, though 

 its extreme rarity (pnly one specimen having been seen to many hun- 

 dreds of the other form) would indicate that it may soon become 

 extinct. 



The only other case of polymorphism in the genus Papilio, at all 

 equal in interest to those I have now brought forward, occurs in Amer- 

 ica ; and we have, fortunately, accurate information about it. Papilio 

 Txirnus, L., is common over almost the whole of temperate North 

 America; and the female resembles the male very closely. A totally 

 different looking insect, both in form and color, Papilio Glaucns, L., 

 inhabits the same region ; and though down to the time when Bois- 

 duval published his " Species General," no connection was supposed to 

 exist between the two species, it is now well asceratuied that P. Glaums 

 is a second female form of P. Turnus. In the "Proceedings of Ento- 

 mological Society of Philadelphia," Jan., 1863, Mr. Walsh gives a very 

 interesting account of the distribution of this species. He tells us that 

 in the New England States, and in New York, all the females are 

 yellow, while in Illinois and further south all are black ; in the inter- 



