ent to decadence. For the weevil, as for ourselves, progress in
matters of food and drink is not always beneficial. The race would
profit better if it remained frugal. On the bean and the vetch the
Bruchus founded colonies in which the infant mortality was low. There
was room for all. On the pea-vine, delicious though its fruits may be,
the greater part of its offspring die of starvation. The rations are
few, and the hungry mouths are multitudinous.

We will linger over this problem no longer. Let us observe the grub
which has now become the sole tenant of the pea by the death of its
brothers. It has had no part in their death; chance has favoured it,
that is all. In the centre of the pea, a wealthy solitude, it performs
the duty of a grub; the sole duty of eating. It nibbles the walls
enclosing it, enlarging its lodgment, which is always entirely filled by
its corpulent body. It is well shaped, fat, and shining with health. If
I disturb it, it turns gently in its niche and sways its head. This is
its manner of complaining of my importunities. Let us leave it in peace.

It profits so greatly and so swiftly by its position that by the time
the dog-days have come it is already preparing for its approaching
liberation. The adult is not sufficiently well equipped to open for
itself a way out through the pea, which is now completely hardened. The
larva knows of this future helplessness, and with consummate art
provides for its release. With its powerful mandibles it bores a channel
of exit, exactly round, with extremely clean-cut sides. The most skilful
ivory-carver could do no better.

To prepare the door of exit in advance is not enough; the grub must also
provide for the tranquillity essential to the delicate processes of
nymphosis. An intruder might enter by the open door and injure the
helpless nymph. This passage must therefore remain closed. But how?

As the grub bores the passage of exit it consumes the farinaceous matter
without leaving a crumb. Having come to the skin of the pea it stops
short. This membrane, semi-translucid, is the door to the chamber of
metamorphosis, its protection against the evil intentions of external
creatures.

It is also the only obstacle which the adult will encounter at the
moment of exit. To lessen the difficulty of opening it the grub takes
the precaution of gnawing at the inner side of the skin, all round the
circumference, so as to make a line of least resistance. The perfect
in