Travel Reference
In-Depth Information
Here again we have a resemblance to the Wart-hogs of Africa, whose upper canines grow
outwards and curve up so as to form a transition from the usual mode of growth to that of
the Babirusa. In other respects there seems no affinity between these animals, and the Babi-
rusa stands completely isolated, having no resemblance to the pigs of any other part of the
world. It is found all over Celebes and in the Sula islands, and also in Bouru, the only spot
beyond the Celebes group to which it extends; and which island also shows some affinity to
the Sula islands in its birds, indicating perhaps, a closer connexion between them at some
former period than now exists.
The other terrestrial mammals of Celebes are, five species of squirrels, which are all dis-
tinct from those of Java and Borneo, and mark the furthest eastward range of the genus in
the tropics; and two of Eastern opossums (Cuscus), which are different from those of the
Moluccas, and mark the furthest westward extension of this genus and of the Marsupial or-
der. Thus we see that the Mammalia of Celebes are no less individual and remarkable than
the birds, since three of the largest and most interesting species have no near allies in sur-
rounding countries, but seem vaguely to indicate a relation to the African continent.
Many groups of insects appear to be especially subject to local influences, their forms and
colours changing with each change of conditions, or even with a change of locality where
the conditions seem almost identical. We should therefore anticipate that the individuality
manifested in the higher animals would be still more prominent in these creatures with less
stable organisms. On the other hand, however, we have to consider that the dispersion and
migration of insects is much more easily effected than that of mammals or even of birds.
They are much more likely to be carried away by violent winds; their eggs may be carried
on leaves either by storms of wind or by floating trees, and their larvæ and pupæ, often bur-
ied in trunks of trees or enclosed in waterproof cocoons, may be floated for days or weeks
uninjured over the ocean. These facilities of distribution tend to assimilate the productions
of adjacent lands in two ways: first, by direct mutual interchange of species; and secondly
by repeated immigrations of fresh individuals of a species common to other islands, which
by intercrossing, tend to obliterate the changes of form and colour, which differences of
conditions might otherwise produce. Bearing these facts in mind, we shall find that the indi-
viduality of the insects of Celebes is even greater than we have any reason to expect.
For the purpose of insuring accuracy in comparisons with other islands, I shall confine
myself to those groups which are best known, or which I have myself carefully studied. Be-
ginning with the Papilionidæ or Swallow-tailed butterflies, Celebes possesses 24 species, of
which the large number of 18 are not found in any other island. If we compare this with
Borneo, which out of 29 species has only two not found elsewhere, the difference is as strik-
