tic surplusage which is psychologically both
unnecessary and unproven, is really only different in degree from that
which Mr Wallace admits in principle when he says that it is probable
that the female is pleased or excited by the display.

Let us for our present purpose leave on one side and regard as sub
judice the question whether the specific details of secondary sexual
characters are the outcome of female choice. For us the question is
whether certain psychological accompaniments of the pairing situation
have influenced the course of evolution and whether these psychological
accompaniments are themselves the outcome of evolution. As a matter of
observation, specially differentiated modes of behaviour, often very
elaborate, frequently requiring highly developed skill, and apparently
highly charged with emotional tone, are the precursors of pairing. They
are generally confined to the males, whose fierce combats during the
period of sexual activity are part of the emotional manifestation. It is
inconceivable that they have no biological meaning; and it is difficult
to conceive that they have any other biological end than to evoke in
the generally more passive female the pairing impulse. They are based
on instinctive foundations ingrained in the nervous constitution
through natural (or may we not say sexual?) selection in virtue of
their profound utility. They are called into play by a specialised
presentation such as the sight or the scent of the female at, or a
little in advance of, a critical period of the physiological rhythm.
There is no necessity that the male should have any knowledge of the
end to which his strenuous activity leads up. In presence of the female
there is an elaborate application of all the energies of behaviour,
just because ages of racial preparation have made him biologically and
emotionally what he is--a functionally sexual male that must dance or
sing or go through hereditary movements of display, when the appropriate
stimulation comes. Of course after the first successful courtship
his future behaviour will be in some degree modified by his previous
experience. No doubt during his first courtship he is gaining the
primary data of a peculiarly rich experience, instinctive and emotional.
But the biological foundations of the behaviour of courtship are laid
in the hereditary coordinations. It would seem that in some cases, not
indeed in all, but perhaps especially in those cases in which second