30 MR. À. R. WALLACE ON THE PAPILIONIDÆ 
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 thirteen species of Papilionidæ 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 Papilionidæ than any other 
in the archipelago, has nevertheless only two peculiar to itself; and it is quite possible, 
and even probable, that one of these may be found 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 J ava, no less 
than eighteen are absolutely restrieted 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 
individuality 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 peeuliar; 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 groups 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 Bre, I believe, without 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-horned _ 
