y has become
useless; the legs which did such good service are no longer required;
and the active slim larva changes into a white fleshy grub, which floats
comfortably in the honey with its mouth just below the surface.

Even in the same group we may find great differences. For instance, in
the family of Insects to which Bees and Wasps belong, some have grub
larvae, such as the Bee and Ant; some have larvae like caterpillars, such
as the Sawflies; and there is a group of minute forms the larvae of which
live inside the eggs of other insects, and present very remarkable and
abnormal forms.

These differences depend mainly on the mode of life and the character of
the food.

RUDIMENTARY ORGANS

Such modifications may be called adaptive, but there are others of a
different origin that have reference to the changes which the race has
passed through in bygone ages. In fact the great majority of animals do
go through metamorphoses (many of them as remarkable, though not so
familiar as those of insects), but in many cases they are passed through
within the egg and thus escape popular observation. Naturalists who
accept the theory of evolution, consider that the development of each
individual represents to a certain extent that which the species has
itself gone through in the lapse of ages; that every individual contains
within itself, so to say, a history of the race. Thus the rudimentary
teeth of Cows, Sheep, Whales, etc. (which never emerge from their
sockets), the rudimentary toes of many mammals, the hind legs of Whales
and of the Boa-constrictor, which are imbedded in the flesh, the
rudimentary collar-bone of the Dog, etc., are indications of descent
from ancestors in which these organs were fully developed. Again, though
used for such different purposes, the paddle of a Whale, the leg of a
Horse and of a Mole, the wing of a Bird or a Bat, and the arm of a Man,
are all constructed on the same model, include corresponding bones, and
are similarly arranged. The long neck of the Giraffe, and the short one
of the Whale (if neck it can be called), contain the same number of
vertebrae.

Even after birth the young of allied species resemble one another much
more than the mature forms. The stripes on the young Lion, the spots on
the young Blackbird, are well-known cases; and we find the same law
prevalent among the lower animals, as, for instance, among Insects and
Crustacea. The Lobster, Crab, Shrimp, and Barnacle are ver