I. THE SUBJECT OF AN IDEA
Love's general psychology.—Love according to natural laws.—Sexual selection.—Man's place in Nature.—Identity of human and animal psychology.—The animal nature of love.
II. THE AIM OF LIFE
The importance of the sexual act.—Its ineluctable character.—Animals who live only to reproduce themselves.—The strife for love, and for death.—Females fecundated at the very instant of birth.—The maintenance of life.
III. SCALE OF SEXES
Asexual reproduction.—Formation of the animal colony.—Limits of asexual reproduction.—Coupling.—Birth of the sexes.—Hermaphrodism and parthenogenesis.—Chemical fecundation.—Universality of parthenogenesis.
IV. SEXUAL DIMORPHISM
1. Invertebrates: formation of the male.—Primitivity of the female.—Minuscule males: the bonellie.—Regression of the male into the male organ: the rirripedes.—Generality of sexual dimorphism.—Superiority of the female in most insect species.—Exceptions.—Numeric dimorphism.—Female hymenoptera.—Multiplicity of her activities.—Male's purely sexual rôle.—Dimorphism of ants and termites.—Grasshoppers and crickets.—Spiders.—Coleoptera.—Glow-worm.—Cochineal's strange dimorphism.
V. SEXUAL DIMORPHISM
2. Vertebrates:—Unnoticeable in fish, saurians, reptiles.—The bird world.—Dimorphism favourable to males: the oriole, pheasants, the ruff.—Peacocks and turkey-cocks.—Birds of paradise.—Moderate dimorphism of mammifers.—Effects of castration on dimorphism.
VI. SEXUAL DIMORPHISM
3. Vertebrates (Continued):—Man and woman.—Characteristics and limits of human dimorphism.—Effects of civilization.—Psychologic dimorphism.—The insect world and the human.—Modern dimorphism, basis of the pair.—Solidarity of the human pair.—Dimorphism and polygamy.—The pair favours the female.—Sexual æsthetics.—Causes of the superiority of feminine beauty.
VII. SEXUAL DIMORPHISM AND FEMINISM
Inferiority and superiority of the female as shown in animal species.—Influence of feeding on the production of sexes.—The female would have sufficed.—Feminism absolute, and moderate.—Pipe-dreams: elimination of the male and human parthenogenesis.
Sexual dimorphism and parallelism.—Sexual organs of man and of woman.—Constancy of sexual parallelism in the animal series.—External sexual organs of placentary mammifera.—Form and position of the penis.—The penial bone.—The clitoris.—The vagina.—The teats.—Forked prong of marsupials. Sexual organs of reptiles.—Fish and birds with a penial organ.—Genital organs of arthropodes.—Attempt to classify animals according to the disposition, presence, absence of exterior organs for reproduction.
IX. THE MECHANISM OF LOVE
1. Copulation: Vertebrates.—Its very numerous varieties and its specific fixity.—The apparent immorality of Nature.—Sexual ethnography.—Human mechanism.—Cavalage.—The form and duration of coupling in divers mammifers.—Aberrations of sexual surgery, the ampallang.—Pain as a bridle on sex.—Maidenhead.—The mole.—Passivity of the female.—The ovule, psychological figure of the female.—Mania of attributing human virtues to animals.—The modesty of elephants.—Coupling mechanism in whales, seals, tortoises.—In certain ophidians and in certain fish.
X. THE MECHANISM OF LOVE
2. Copulation (Continued)—Arthropodes.—Scorpions.—Large aquatic crustaceans.—Small crustaceans.—The hydrachne.—Scutilary.—Cockchafer.—Butterflies.—Flies, etc.—Variation of animals' sexual habits.
XI. THE MECHANISM OF LOVE
3. Of birds and fish.—Males without penis.—Coupling by simple contact.—Salacity of birds.—Copulation of batrachians: accoucheur toad, aquatic toad, earth toad, pipa toad.—Fœtal parasitism.—Chastity of fish.—Sexes separated in love.—Onanistic fecundation.—Cephalopodes, the spermatophore.
XII. THE MECHANISM OF LOVE
4. Hermaphrodism.—Sexual life of oysters.—Gasteropodes.—The idea of reproduction and the idea of pleasure.—Mechanism of reciprocal reproduction: helices.—Spintrian habits.—Reflection on hermaphrodism.
XIII. THE MECHANISM OF LOVE
5. Artificial fecundation.—Disjunction of the secreting apparatus from the copulating apparatus.—Spiders.—Discovery of their copulative method.—Brutality of the female.—Habits of the epeire.—The argyronete.—The tarantula.—Exceptions: the reapers.—Dragonflies (libellule).—Dragonflies (demoiselle) virgins and "jouvencelle."—Picture of their love affairs.
XIV. THE MECHANISM OF LOVE
6. Cannibalism in sex.—Females who devour the male, those who devour the spermatophore.—Probable use of these practices.—Fecundation by the whole male.—Loves of the white foreheaded dectic.—The green grasshopper.—The Alpine analote.—The ephippigere.—Further reflections on the cannibalism of sex.—Loves of the praying mantis.