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



P. Coon, but with red instead of yellow spots (P. Douhledayl, Wall.), the corresponding 

 variety of P. Androgens (P. Achates, Cram., 182, a, b,) has acquired exactly the same 

 peculiarity of ha%TJig red spots instead of yellow. Lastly, in the island of Timor, the 

 female of P. (Enomaus (a species allied to P. Memnon) resembles so closely P. lAris 

 (one of the Pobjdonis-gvovi]}), that the two, which were often seen flying together, could 

 only be distinguished by a minute comparison after being captui-ed. 



The last six cases of mimicry are especially instructive, because they seem to indicate 

 one of the processes by which dimorphic forms have been produced. When, as in these 

 cases, one sex differs much from the other, and varies greatly itself, it may happen that 

 occasionally individual variations will occur having a distant resemblance to groups which 

 are the objects of mimicry, and which it is therefore advantageous to resemble. Such 

 a variety will have a better chance of preservation ; the individuals possessing it will be 

 multiplied ; and their accidental likeness to the favoured group ^^nll be rendered perma- 

 nent by hereditary transmission, and, each successive variation which increases the re- 

 semblance being preserved, and aU variations departing from the favoured type haAing 

 less chance of preservation, there will in time result those singular cases of two or more 

 isolated and fixed forms bound together by that intimate relationship which constitutes 

 them the sexes of a single species. The reason why the females are more subject to this 

 kind of modification than the males is, probably, that their slower flight, when laden 

 with eggs, and their exposure to attack whUe in the act of depositing their eggs upon 

 leaves, render it especially advantageous for them to have some additional protection. 

 This they at once obtain by acquiring a resemblance to other species which, from what- 

 ever cause, enjoy a comparative immunity from persecution. 



This summary of the more interesting phenomena of variation presented by the eastern 

 Papilionida3 is, I think, sufficient to substantiate my position, that the Lepidoptera are 

 a group that offer especial facilities for such inquiries ; and it will also show that they 

 have undergone an amount of special adaptive modification rarely equalled among the 

 the more highly organized animals. And, among the Lepidoptera, the great and pre- 

 eminently tropical families of Papilionidae and Danaidfs seem to be those in which com- 

 plicated adaptations to the surrounding organic and inorganic universe have been most 

 completely developed, offering in this respect a striking analogy to the equally extraor- 

 dinary, though totaDy different, adaptations which present themselves in the Orchidece, 

 the only family of plants in which mimicry of other organisms appears to play any im- 

 portant part, and the only one in which striking cases of polymorphism occur ; for such 

 we must consider to be the male, female, and hermaphrodite forms of Catasetum tri- 

 dentatum, which differ so greatly in form and structure that they were long considered 

 to belong to three distinct genera. 



Arrangement and Geographical Distribution of the Malayan PapUionidaj. 

 Although the species of Papilionidoe inhabiting the Malayan region are very numerous, 

 they all belong to three out of the nine genera into which the family is divided. One of 

 the remaining genera (Emycus) is restricted to Australia, and another (Teinojyaljms) to the 

 Himalayan Moimtains, while no less than four {Parnassius, Doritis, Thais, and Sericinus) 

 are confined to Southern Europe and to the mountain-ranges of the Palsearctic region. 



