w away and
finish off the angles of a cell till a large part both of that cell and
of the adjoining cells has been built. This capacity in bees of laying
down under certain circumstances a rough wall in its proper place
between two just-commenced cells, is important, as it bears on a fact,
which seems at first quite subversive of the foregoing theory; namely,
that the cells on the extreme margin of wasp-combs are sometimes
strictly hexagonal; but I have not space here to enter on this subject.
Nor does there seem to me any great difficulty in a single insect (as
in the case of a queen-wasp) making hexagonal cells, if she work
alternately on the inside and outside of two or three cells commenced at
the same time, always standing at the proper relative distance from
the parts of the cells just begun, sweeping spheres or cylinders, and
building up intermediate planes. It is even conceivable that an insect
might, by fixing on a point at which to commence a cell, and then moving
outside, first to one point, and then to five other points, at the
proper relative distances from the central point and from each other,
strike the planes of intersection, and so make an isolated hexagon: but
I am not aware that any such case has been observed; nor would any good
be derived from a single hexagon being built, as in its construction
more materials would be required than for a cylinder.

As natural selection acts only by the accumulation of slight
modifications of structure or instinct, each profitable to the
individual under its conditions of life, it may reasonably be asked, how
a long and graduated succession of modified architectural instincts,
all tending towards the present perfect plan of construction, could
have profited the progenitors of the hive-bee? I think the answer is
not difficult: it is known that bees are often hard pressed to get
sufficient nectar; and I am informed by Mr. Tegetmeier that it has been
experimentally found that no less than from twelve to fifteen pounds of
dry sugar are consumed by a hive of bees for the secretion of each pound
of wax; so that a prodigious quantity of fluid nectar must be collected
and consumed by the bees in a hive for the secretion of the wax
necessary for the construction of their combs. Moreover, many bees have
to remain idle for many days during the process of secretion. A large
store of honey is indispensable to support a large stock of bees during
the winter; and the security of