Pearson’s Investigations 
on spiders, in a state of nature. Such observa- 
tions demonstrate that selective mating occurs 
in nature, but, for the most part, fail to show what 
it is that determines the choice. 
D. Dewar, however, states (Birds of the Plains, 
p. 42) that the coloured peahens in the Zoo- 
logical Gardens at Lahore show a decided pre- 
ference for the white cocks, which are kept in 
the aviary along with normally coloured cocks. 
He gives it as his opinion that “the hens select 
the white cocks, not because they are white, but 
because of the strength of the sexual instincts of 
these latter. The white cocks continually show 
off before the hens ; the sexual desire is developed 
more highly in them than in the ordinary cocks, 
and it is this that attracts the hens.” 
The only zoologists who have investigated 
experimentally ‘the question of sexual selection 
appear to be Karl Pearson and Frank Finn. 
The former tried to determine, by actual measure- 
ments, whether there is any preferential mating 
among human beings as regards physical char- 
acteristics. ‘‘ Our statistics,” he writes, on page 
427 of The Grammar of Sczence, “run to only 
a few hundreds, and were not collected ad hoc. 
Still, as far as they go, they show no evi- 
dence of preferential mating in mankind on 
the basis of stature, or of any character very 
closely correlated with stature. Men do not 
appear, for example, to select tall women for 
399 
