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 such pupae originally stored as food might become developed; and the foreign 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, 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.