. Figure 2 shows the abrupt bend
over the base of the wing in Papilio miletus of Celebes, compared with
the slight curvature in the common Papilio sarpedon, which has almost
exactly the same form from India to New Guinea and Australia. Figure
3 shows the elongated wing of Tachyris zarinda, a native of Celebes,
compared with the much shorter wing of Tachyris nero, a very closely
allied species found in all the western islands. The difference of form
is in each case sufficiently obvious, but when the insects themselves
are compared, it is much more striking than in these partial outlines.

From the analogy of birds, we should suppose that the pointed wing
gave increased rapidity of flight, since it is a character of terns,
swallows, falcons, and of the swift-flying pigeons. A short and rounded
wing, on the other hand, always accompanies a more feeble or more
laborious flight, and one much less under command. We might suppose,
therefore, that the butterflies which possess this peculiar form were
better able to escape pursuit. But there seems no unusual abundance of
insectivorous birds to render this necessary; and as we cannot believe
that such a curious peculiarity is without meaning, it seems probable
that it is the result of a former condition of things, when the island
possessed a much richer fauna, the relics of which we see in the
isolated birds and Mammalia now inhabiting it; and when the abundance
of insectivorous creatures rendered some unusual means of escape
a necessity for the large-winged and showy butterflies. It is some
confirmation of this view, that neither the very small nor the very
obscurely coloured groups of butterflies have elongated wings, nor is
any modification perceptible in those strong-winged groups which already
possess great strength and rapidity of flight. These were already
sufficiently protected from their enemies, and did not require increased
power of escaping from them. It is not at all clear what effect the
peculiar curvature of the wings has in modifying flight.

Another curious feature in the zoology of Celebes is also worthy of
attention. I allude to the absence of several groups which are found on
both sides of it, in the Indo-Malay islands as well as in the Moluccas;
and which thus seem to be unable, from some unknown cause, to obtain a
footing in the intervening island. In Birds we have the two families of
Podargidae and Laniadae, which range over the whole Archipelago and into