SEXUAL COLOUR 85 
become conspicuous in order to be killed, 
only less conspicuous ones will be left to 
carry on the species, and conspicuousness 
will thus be quickly eradicated by Natural 
Selection. 
It is obvious that this criticism cannot be 
levelled at the author’s theory, which in some 
respects is not unlike Stolzmann’s. The 
author’s theory deals with the pair, male and 
female associated together at the breeding 
season or during copulation ; under these con- 
ditions the destruction of a conspicuous male 
by no means precludes that his characters will 
not be handed down to the next generation. 
He most probably will have already fertilised 
the female either partially or entirely. It 
may here be noted that secondary sexual 
characters are at their highest development 
at the time when the female is ready to be 
fertilised ; male birds, for instance, are in their 
most brilliant plumage, not during their nest- 
ing season, but at a considerable time before 
this, in either the last of winter or the first 
of spring. 
The relative proportion of males to females 
is, as Stolzmann concludes, a most important 
factor in the welfare of the species. Accord- 
ing to the theory, great excess of males 
