ave just stolen it from its owner, who would not have been
long before laying her egg in it. What will the Mason do in the presence
of this munificent gift, which saves her the trouble of building and
harvesting? She will leave the mortar no doubt, finish storing the
Bee-bread, lay her egg and seal up. A mistake, an utter mistake:
our logic is not the logic of the insect, which obeys an inevitable,
unconscious prompting. It has no choice as to what it shall do; it
cannot discriminate between what is and what is not advisable; it
glides, as it were, down an irresistible slope prepared beforehand to
bring it to a definite end. This is what the facts that still remain to
be stated proclaim with no uncertain voice.

The Bee who was building and to whom I offer a cell ready-built and full
of honey does not lay aside her mortar for that. She was doing mason's
work; and, once on that tack, guided by the unconscious impulse, she
has to keep masoning, even though her labour be useless, superfluous
and opposed to her interests. The cell which I give her is certainly
perfect, looked upon as a building, in the opinion of the master-builder
herself, since the Bee from whom I took it was completing the provision
of honey. To touch it up, especially to add to it, is useless and, what
is more, absurd. No matter: the Bee who was masoning will mason. On the
aperture of the honey-store she lays a first course of mortar, followed
by another and yet another, until at last the cell is a third taller
then the regulation height. The masonry-task is now done, not as
perfectly, it is true, as if the Bee had gone on with the cell whose
foundations she was laying at the moment when I exchanged the nests, but
still to an extent which is more than enough to prove the overpowering
impulse which the builder obeys. Next comes the victualling, which is
also cut short, lest the honey-store swelled by the joint contributions
of the two Bees should overflow. Thus the Mason-bee who is beginning
to build and to whom we give a complete cell, a cell filled with honey,
makes no change in the order of her work: she builds first and then
victuals. Only she shortens her work, her instinct warning her that the
height of the cell and the quantity of honey are beginning to assume
extravagant proportions.

The converse is equally conclusive. To a Mason-bee engaged in
victualling I give a nest with a cell only just begun and not at all fit
to receive the paste. This c