developed or from indolent habit, will
have had the best chance of surviving from not being blown out to sea;
and, on the other hand, those beetles which most readily took to flight
will oftenest have been blown to sea and thus have been destroyed.

The insects in Madeira which are not ground-feeders, and which, as the
flower-feeding coleoptera and lepidoptera, must habitually use their
wings to gain their subsistence, have, as Mr. Wollaston suspects, their
wings not at all reduced, but even enlarged. This is quite compatible
with the action of natural selection. For when a new insect first
arrived on the island, the tendency of natural selection to enlarge
or to reduce the wings, would depend on whether a greater number of
individuals were saved by successfully battling with the winds, or
by giving up the attempt and rarely or never flying. As with mariners
shipwrecked near a coast, it would have been better for the good
swimmers if they had been able to swim still further, whereas it would
have been better for the bad swimmers if they had not been able to swim
at all and had stuck to the wreck.

The eyes of moles and of some burrowing rodents are rudimentary in size,
and in some cases are quite covered up by skin and fur. This state of
the eyes is probably due to gradual reduction from disuse, but aided
perhaps by natural selection. In South America, a burrowing rodent, the
tuco-tuco, or Ctenomys, is even more subterranean in its habits than the
mole; and I was assured by a Spaniard, who had often caught them, that
they were frequently blind; one which I kept alive was certainly in
this condition, the cause, as appeared on dissection, having been
inflammation of the nictitating membrane. As frequent inflammation of
the eyes must be injurious to any animal, and as eyes are certainly not
indispensable to animals with subterranean habits, a reduction in their
size with the adhesion of the eyelids and growth of fur over them,
might in such case be an advantage; and if so, natural selection would
constantly aid the effects of disuse.

It is well known that several animals, belonging to the most different
classes, which inhabit the caves of Styria and of Kentucky, are blind.
In some of the crabs the foot-stalk for the eye remains, though the eye
is gone; the stand for the telescope is there, though the telescope
with its glasses has been lost. As it is difficult to imagine that
eyes, though useless, could be in any way in