from their silken parachutes, and presenting to the lover of nature a
far more interesting spectacle than the balloon of the philosopher. One
of these natural aëronauts I followed, which, sailing in the sunbeams,
had two distinct and widely diverging fasciculi of webs, and their
position in the air was such, that a line uniting them would have been
at right angles with the direction of the breeze."--_Mag. Natural
History_.


_The Ichneumon Fly_.

There are several species of ichneumon which make thinnings among the
caterpillars of the cabbage butterfly. The process of one species
is this:--while the caterpillar is feeding, the ichneumon fly hovers
over it, and, with its piercer, perforates the fatty part of the
caterpillar's back in many places, and in each deposits an egg, by
means of the two parts of the sheath uniting together, and thus forming
a tube down which the egg is conveyed into the perforation made by the
piercer of the fly. The caterpillar unconscious of what will ensue keeps
feeding on, until it changes into a chrysalis; while in that torpid
state, the eggs of the ichneumon are hatched, and the interior of the
body of the caterpillar serves as food for the caterpillars of the
ichneumon fly. When these have fed their accustomed time, and are about
to change into the pupa state, they, by an instinct given them, attack
the vital part of the caterpillar (a most wonderful economy in nature,
that this process should be delayed until they have no more occasion
for food.) They then spin themselves minute cases within the body of
the caterpillar; and instead of a butterfly coming forth (which, if a
female, would have probably laid six hundred eggs, thus producing as
many caterpillars, whose food would be the cabbage,) a race of these