re either without wings or have their
wings in a useless and merely rudimentary state; and that a large number
of kinds which are very common on the nearest mainland, but which are
compelled to use their wings in seeking their food, are here entirely
wanting. It is also observed that the beetles on this island generally
lie much concealed until the wind lulls and the sun shines. These are
the facts; let us now see how Lamarck would treat them.

Lamarck would say that the beetles once being on this island it became
one of the conditions of their existence that they should not get blown
out to sea. For once blown out to sea, they would be quite certain to be
drowned. Beetles, when they fly, generally fly for some purpose, and do
not like having that purpose interfered with by something which can
carry them all-whithers, whether they like it or no. If they are flying
and find the wind taking them in a wrong direction, or seaward--which
they know will be fatal to them--they stop flying as soon as may be, and
alight on _terra firma_. But if the wind is very prevalent the beetles
can find but little opportunity for flying at all: they will therefore
lie quiet all day and do as best they can to get their living on foot
instead of on the wing. There will thus be a long-continued disuse of
wings, and this will gradually diminish the development of the wings
themselves, till after a sufficient number of generations these will
either disappear altogether, or be seen in a rudimentary condition only.
For each beetle which has made but little use of its wings will be
liable to leave offspring with a slightly diminished wing, some other
organ which has been used instead of the wing becoming proportionately
developed. It is thus seen that the conditions of existence are the
indirect cause of the wings becoming rudimentary, inasmuch as they
preclude the beetles from using them; the disuse however on the part of
the beetles themselves is the direct cause.

Now let us see how Mr. Darwin deals with the same case. He writes:--

"In some cases we might easily set down to disuse, modifications of
structure which are _wholly_ or _mainly_ due to natural selection." Then
follow the facts about the beetles of Madeira, as I have given them
above. While we are reading them we naturally make up our minds that
the winglessness of the beetles will prove due either wholly, or at any
rate mainly, to natural selection, and that though it would be easy t