and as limited by sex Relations between the several forms of
inheritance Causes why one sex and the young are not modified through
sexual selection Supplement on the proportional numbers of the two
sexes throughout the animal kingdom The proportion of the sexes in
relation to natural selection.
CHAPTER IX.
SECONDARY SEXUAL CHARACTERS IN THE LOWER CLASSES OF THE ANIMAL KINGDOM.
These characters are absent in the lowest classes Brilliant
colours Mollusca Annelids Crustacea, secondary sexual characters
strongly developed; dimorphism; colour; characters not acquired before
maturity Spiders, sexual colours of; stridulation by the
males Myriapoda.
CHAPTER X.
SECONDARY SEXUAL CHARACTERS OF INSECTS.
Diversified structures possessed by the males for seizing the
females Differences between the sexes, of which the meaning is not
understood Difference in size between the
sexes Thysanura Diptera Hemiptera Homoptera, musical powers possessed
by the males alone Orthoptera, musical instruments of the males, much
diversified in structure; pugnacity; colours Neuroptera, sexual
differences in colour Hymenoptera, pugnacity and odours Coleoptera,
colours; furnished with great horns, apparently as an ornament;
battles; stridulating organs generally common to both sexes.
CHAPTER XI.
INSECTS, continued. ORDER LEPIDOPTERA. (BUTTERFLIES AND MOTHS.)
Courtship of Butterflies Battles Ticking noise Colours common to both
sexes, or more brilliant in the males Examples Not due to the direct
action of the conditions of life Colours adapted for protection Colours
of moths Display Perceptive powers of the
Lepidoptera Variability Causes of the difference in colour between the
males and females Mimicry, female butterflies more brilliantly coloured
than the males Bright colours of caterpillars Summary and concluding
remarks on the secondary sexual character of insects Birds and insects
compared.
CHAPTER XII.
SECONDARY SEXUAL CHARACTERS OF FISHES, AMPHIBIANS, AND REPTILES.
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