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,
natural selection might increase and modify 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 effected by a crowd of bees working in
a dark hive. Granting whatever instincts you please, 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 at first appears: all this beautiful work can be shown,
I think, to follow from a few simple instincts.