ed with a lid of the same material. We thus become
aware, for the second time, that, when the Mason-bee is stopped by
a paper barrier, the reason is not her incapacity to overcome the
obstacle. On the other hand, the occupants of the nest covered with the
cone, after making their way through the earthen dome, finding the sheet
of paper at some distance, do not even try to perforate this obstacle,
which they would have conquered so easily had it been fastened to the
nest. They die under the cover without making any attempt to escape.
Even so did Reaumur's Bees perish in the glass funnel, where their
liberty depended only upon their cutting through a bit of gauze.

This fact strikes me as rich in inferences. What! Here are sturdy
insects, to whom boring through granite is mere play, to whom a stopper
of soft wood and a paper partition are walls quite easy to perforate
despite the novelty of the material; and yet these vigorous
housebreakers allow themselves to perish stupidly in the prison of a
paper bag, which they could have torn open with one stroke of their
mandibles! They are capable of tearing it, but they do not dream of
doing so! There can be only one explanation of this suicidal inaction.
The insect is well-endowed with tools and instinctive faculties for
accomplishing the final act of its metamorphosis, namely, the act of
emerging from the cocoon and from the cell. Its mandibles provide it
with scissors, file, pick-axe and lever wherewith to cut, gnaw through
and demolish either its cocoon and its mortar enclosure or any other not
too obstinate barrier substituted for the natural covering of the nest.
Moreover--and this is an important proviso, except for which the outfit
would be useless--it has, I will not say the will to use those tools,
but a secret stimulus inviting it to employ them. When the hour for the
emergence arrives, this stimulus is aroused and the insect sets to work
to bore a passage. It little cares in this case whether the material to
be pierced be the natural mortar, sorghum-pith, or paper: the lid that
holds it imprisoned does not resist for long. Nor even does it care if
the obstacle be increased in thickness and a paper wall be added outside
the wall of clay: the two barriers, with no interval between them, form
but one to the Bee, who passes through them because the act of getting
out is still one act and one only. With the paper cone, whose wall is a
little way off, the conditions are chan