102 CONTROLLED NATURAL SELECTION 
tection of their young (instinctively), why 
should not similar performances and exhibi- 
tions on the part of the male, be to protect 
the female?) A more detailed comparison of 
the means the parent uses to protect the 
young, with the pre-copulatory displays of the 
male, shows how strikingly similar are not 
only the methods used, but the actual move- 
ments, positions, and sounds, &c., made. In 
one case a given stimulus, the presence of an 
enemy coupled with possession of young, 
causes the parent to instinctively react ; in 
the other a given stimulus, the presence of 
an enemy, either real or assumed, coupled 
with the sexual possession of a female, causes 
the male to react ina similar manner. And 
just as attracting instincts in both sexes serve 
to protect the young, and in the male to 
protect the female, so the attracting colour 
of parents and males will have the same 
effect. 
Further, these displays, pre-copulatory and 
for young protection, are often made when 
neither females nor young are present, but at 
the approach of an enemy; they are then 
called expressions of fear, instead of reactions 
to a stimulus. May not this be the stimulus 
always, no matter when they are displayed ? 
