Darwin's Theory of Sexual Selection 179 
gives a graphic account of the agile way in which the dimin- 
utive male escapes from the ferocity of the female, by gliding 
about and playing hide and seek over her body and along her 
gigantic limbs: in such a pursuit it is evident that the 
chances of escape would be in favor of the smallest males, 
while the larger ones would fall early victims ; thus gradually 
a diminutive race of males would be selected, until at last 
they would dwindle to the smallest possible size compatible 
with the exercise of their generative functions, —in fact 
probably to the size we now see them, 7.¢. so small as to be 
a sort of parasite upon the female, and either beneath her 
notice, or too agile and too small for her to catch without 
great difficulty.’ ” 
It is certainly surprising to find Darwin ascribing even 
this difference in size between the sexes to the action of 
selection. Is it not a little ludicrous to suppose that the 
females have reduced the males to a size too small for them 
to catch? 
There are many cases known in the animal kingdom where 
there is a difference in size between the two sexes, especially 
in the group of insects; but I doubt very much if they are to 
be accounted for as the result of sexual selection. In some 
of these cases Darwin accounts for the larger size of the 
female, on account of the large number of eggs which she 
has to carry. In other insects where the male is larger, 
as in the stag-beetle, the size is ascribed to the conflicts of 
the males, leading to the survival of the larger individuals. 
In still other cases, where the males are larger, but do not 
fight, an explanation is admittedly wanting; but it is suggested 
that here there would be no necessity for the males to be 
smaller than the females in order to mature before them (as 
is supposed to happen in other species), for in these cases 
the individuals are not short-lived, and there would be ample 
time for pairing. Again, although the males of nearly all 
bees are smaller than the females, yet the reverse is true in 
