Where the forest vetch is lacking, the Bruchus, none the less, bestows
its habitual prodigality of eggs upon another vegetable of similar
flavor, but incapable of nourishing all the grubs: for example, the
travelling vetch (_Vicia peregrina_) or the cultivated vetch (_Vicia
saliva_). The number of eggs remains high even upon insufficient pods,
because the original food-plant offered a copious provision, both in the
multiplicity and the size of the seeds. If the Bruchus is really a
stranger, let us regard the bean as the original food-plant; if
indigenous, the large vetch.

Sometime in the remote past we received the pea, growing it at first in
the prehistoric vegetable garden which already supplied the bean. It was
found a better article of diet than the broad bean, which to-day, after
such good service, is comparatively neglected. The weevil was of the
same opinion as man, and without entirely forgetting the bean and the
vetch it established the greater part of its tribe upon the pea, which
from century to century was more widely cultivated. To-day we have to
share our peas; the Bruchidae take what they need, and bestow their
leavings on us.

This prosperity of the insect which is the offspring of the abundance
and equality of our garden products is from another point of view
equivalent 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.