ve them. Smelling their road cautiously to the ends of the
branches, they soon reach their own particular aphides, whose bodies
they proceed gently to stroke with their outstretched feelers, and then
stand by quietly for a moment in happy anticipation of the coming
dinner. Presently, the obedient aphis, conscious of its lawful master's
friendly presence, begins slowly to emit from two long horn-like tubes
near the centre of its back a couple of limpid drops of a sticky pale
yellow fluid. Honey-dew our English rustics still call it, because, when
the aphides are not milked often enough by ants, they discharge it
awkwardly of their own accord, and then it falls as a sweet clammy dew
upon the grass beneath them. The ant, approaching the two tubes with
cautious tenderness, removes the sweet drops without injuring in any way
his little _protege_, and then passes on to the next in order of his
tiny cattle, leaving the aphis apparently as much relieved by the
process as a cow with a full hanging udder is relieved by the timely
attention of the human milkmaid.

Evidently, this is a case of mutual accommodation in the political
economy of the ants and aphides: a free interchange of services between
the ant as consumer and the aphis as producer. Why the aphides should
have acquired the curious necessity for getting rid of this sweet,
sticky, and nutritious secretion nobody knows with certainty; but it is
at least quite clear that the liquid is a considerable nuisance to them
in their very sedentary and monotonous existence--a waste product of
which they are anxious to disembarrass themselves as easily as
possible--and that while they themselves stand to the ants in the
relation of purveyors of food supply, the ants in return stand to them
in the relation of scavengers, or contractors for the removal of useless
accumulations.

Everybody knows the aphides well by sight, in one of their forms at
least, the familiar rose aphis; but probably few people ever look at
them closely and critically enough to observe how very beautiful and
wonderful is the organisation of their tiny limbs in all its exquisite
detail. If you pick off one good-sized wingless insect, however, from a
blighted rose-leaf, and put him on a glass slide under a low power of
the microscope, you will most likely be quite surprised to find what a
lovely little creature it is that you have been poisoning wholesale all
your life long with diluted tobacco-juice. His body