In addition to their other organs, flying insects are furnished
with wings. Some insects are dipterous or double-winged, as the fly;
others are tetrapterous or furnished with four wings, as the bee; and,
by the way, no insect with only two wings has a sting in the rear.
Again, some winged insects have a sheath or shard for their wings,
as the cockchafer; whereas in others the wings are unsheathed, as in
the bee. But in the case of all alike, flight is in no way modified by
tail-steerage, and the wing is devoid of quill-structure or division
of any kind.