into the umbilical excrescence, which is less easy of perforation than
those parts protected by the skin alone. It is even possible that the
umbilicum, whose organization differs from that of the rest of the pea,
contains a peculiar sap that is distasteful to the little grub.

Such, doubtless, is the reason why the peas exploited by the Bruchus are
still able to germinate. They are damaged, but not dead, because the
invasion was conducted from the free hemisphere, a portion less
vulnerable and more easy of access. Moreover, as the pea in its entirety
is too large for a single grub to consume, the consumption is limited to
the portion preferred by the consumer, and this portion is not the
essential portion of the pea.

With other conditions, with very much smaller or very much larger seeds,
we shall observe very different results. If too small, the germ will
perish, gnawed like the rest by the insufficiently provisioned inmate;
if too large, the abundance of food will permit of several inmates.
Exploited in the absence of the pea, the cultivated vetch and the broad
bean afford us an excellent example; the smaller seed, of which all but
the skin is devoured, is left incapable of germination; but the large
bean, even though it may have held a number of grubs, is still capable
of sprouting.

Knowing that the pod always exhibits a number of eggs greatly in excess
of the enclosed peas, and that each pea is the exclusive property of one
grub, we naturally ask what becomes of the superfluous grubs. Do they
perish outside when the more precocious have one by one taken their
places in their vegetable larder? or do they succumb to the intolerant
teeth of the first occupants? Neither explanation is correct. Let us
relate the facts.