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



furnished by a single group of insects would have had but little weight on a point of such 

 magnitude if standing alone ; but coming as it does to confirm deductions drawn from 

 whole classes of the higher animals, it must be admitted to have considerable value. 



We may determine in a similar manner the relations of the different Papuan Islands to 

 New Guinea. Of tliirteen species of PapUionidEe obtained in the Aru Islands, five were also 

 found in New Guinea, and eight not. Of nine species obtained at Waigiou, five were New 

 Guinea, and four not. The five species found at Mysol were all New Guinea species. 

 Mysol, therefore, has closer relations to New Guinea than the other islands ; and this is 

 corroborated by the distribution of the birds, of which I will only now give one instance. 

 The Paradise Bird found in Mysol is the common New Guinea species, while the Aru 

 Islands and Waigiou have each a species peculiar to themselves. 



The large island of Borneo, which contains more species of Papilionidae than any other 

 in the archipelago, has nevertheless only two pectdiar to itself; and it is qmte possible, 

 and even probable, that one of these may be foimd in Sumatra or Java. The last-named 

 island has also two species peculiar to it; Sumatra has not one, and the peninsula of 

 Malacca only one. The identity of species is even greater than in birds or in most other 

 groups of insects, and points very strongly to a recent connexion of the whole with each 

 other and the continent. But when we pass to the next island (Celebes), separated from 

 them by a strait not wider than that which divides them from each other, we have a strik- 

 ing contrast ; for with a total number of species less than either Borneo or Java, no less 

 than eighteen are absolutely restricted to it. Further east, the large islands of Ceram 

 and New Guinea have only three species peculiar to each, and Timor has five. We shall 

 have to look, not to single islands, but to whole groups, in order to obtain an amount of 

 indi\'iduality comparable with that of Celebes. For example, the extensive group com- 

 prising the large islands of Java, Borneo, and Sumatra, with the peninsula of Malacca, 

 possessing altogether 45 species, has about 21, or less than half, peculiar to it ; the nu- 

 merous group of the Philippines possess 21 species, of which 16 are peculiar ; the seven 

 chief islands of the Moluccas have 27, of which 12 are peculiar ; and the whole of the 

 Papuan Islands, with an equal number of species, have 17 peculiar. Comparable with 

 the most isolated of these groups is Celebes, with its 24 species, of which the large pro- 

 portion of 18 are peculiar. We see, therefore, that the opinion I have already expressed, 

 in the papers before quoted, of the high degree of isolation and the remarkable distinctive 

 features of this interesting island, is fully borne out by the examination of this conspi- 

 cuous family of insects. A single straggling island, with a few small satellites, it is 

 zoologically of equal importance with extensive gi-oups of islands many times as large as 

 itself ; and standing in the very centre of the archipelago, surrounded on every side with 

 islets connecting it with the larger groups, and which seem to afford the greatest facilities 

 for the migration and intercommunication of their respective productions, it yet stands 

 out conspicuous with a character of its own in every department of nature, and presents 

 peculiarities which are, I believe, -w-ithout a parallel in any similar locality on the globe. 



Briefly to summarize these peculiarities, Celebes possesses three genera of mammals 

 (out of the very small number which inhabit it) which are of singular and isolated 

 forms, viz., Cynopithecus, a tailless Ape allied to the Baboons ; Anoa, a straight-homed 



