the nest to collect building materials
and food for themselves, their slaves and larvae. So that the masters in
this country receive much less service from their slaves than they do in
Switzerland.

By what steps the instinct of F. sanguinea originated I will not pretend
to conjecture. But as ants, which are not slave-makers, will, as I have
seen, carry off pupae of other species, if scattered near their nests,
it is possible that pupae originally stored as food might become
developed; and the ants thus unintentionally reared would then follow
their proper instincts, and do what work they could. If their presence
proved useful to the species which had seized them--if it were more
advantageous to this species to capture workers than to procreate
them--the habit of collecting pupae originally for food might by natural
selection be strengthened and rendered permanent for the very different
purpose of raising slaves. When the instinct was once acquired, if
carried out to a much less extent even than in our British F. sanguinea,
which, as we have seen, is less aided by its slaves than the same
species in Switzerland, I can see no difficulty in natural selection
increasing and modifying the instinct--always supposing each
modification to be of use to the species--until an ant was formed as
abjectly dependent on its slaves as is the Formica rufescens.

CELL-MAKING INSTINCT OF THE HIVE-BEE.

I will not here enter on minute details on this subject, but will merely
give an outline of the conclusions at which I have arrived. He must be
a dull man who can examine the exquisite structure of a comb, so
beautifully adapted to its end, without enthusiastic admiration. We
hear from mathematicians that bees have practically solved a recondite
problem, and have made their cells of the proper shape to hold the
greatest possible amount of honey, with the least possible consumption
of precious wax in their construction. It has been remarked that a
skilful workman, with fitting tools and measures, would find it
very difficult to make cells of wax of the true form, though this is
perfectly effected by a crowd of bees working in a dark hive. Grant
whatever instincts you please, and it seems at first quite inconceivable
how they can make all the necessary angles and planes, or even perceive
when they are correctly made. But the difficulty is not nearly so great
as it at first appears: all this beautiful work can be shown, I think,
to follow f