Chap. VIII. 
SEXUAL SELECTION. 
261 
attractive males. Unless tliis result followed, the cha- 
racters which gave to certain males an advantage over 
others, could not be perfected and augmented through 
sexual selection. When the sexes exist in exactly 
equal numbers, the worst-endowed males will ultimately 
find females (excepting where polygamy prevails), and 
leave as many offspring, equally well fitted for their 
general habits of life, as the best-endowed males. From 
various facts and considerations, I formerly inferred 
that with most animals, in which secondary sexual 
characters were well developed, the males considerably 
exceeded the females in number; and this does hold 
good in some few cases. If the males were to the 
females as two to one, or as three to two, or even in 
a somewhat lower ratio, the whole affair would be 
simple ; for the better-armed or more attractive males 
would leave the largest number of offspring. But after 
investigating, as far as possible, the numerical propor- 
tions of the sexes, I do not believe that any great 
inequality in number commonly exists. In most cases 
sexual selection appears to have been effective in the 
following manner. 
Let us take any species, a bird for instance, and 
divide the females inhabiting a district into two equal 
bodies: the one consisting of the more vigorous and 
better-nourished individuals, and the other of the less 
vigorous and healthy. The former, there can be little 
doubt, would be ready to breed in the spring before the 
others ; and this is the opinion of Mr. Jenner Weir, who 
has during many years carefully attended to the habits 
of birds. There can also be no doubt that the most 
vigorous, healthy, and best-nourished females would on 
an average succeed in rearing the largest number of 
offspring. The males, as we have seen, are generally 
ready to breed before the females ; of the males the 
