The three Climatal Zones of the Earth--Temperature of the Equatorial Zone--Causes of the Uniform High Temperature near the Equator--Influence of the Heat of the Soil--Influence of the Aqueous Vapour of the Atmosphere--Influence of Winds on the Temperature of the Equator--Heat due to the Condensation of Atmospheric Vapour--General Features of the Equatorial Climate--Uniformity of the Equatorial Climate in all Parts of the Globe--Effects of Vegetation on Climate--Short Twilight of the Equatorial Zone--The Aspect of the Equatorial Heavens--Intensity of Meteorological Phenomena at the Equator--Concluding Remarks _pages 1-26_ II. Equatorial Vegetation. The Equatorial Forest-belt and its Causes--General Features of the Equatorial Forests--Low-growth Forest-trees--Flowery Trunks and their Probable Cause--Uses of Equatorial Forest-trees--The Climbing Plants of the Equatorial Forests--Palms--Uses of Palm-trees and their Products--Ferns--Ginger-worts and Wild Bananas--Arums--Screw-Pines--Orchids--Bamboos--Uses of the Bamboo--Mangroves--Sensitive-plants--Comparative Scarcity of Flowers--Concluding Remarks on Tropical Vegetation _pages 27-68_ III. Animal Life in the Tropical Forests. Difficulties of the Subject--General Aspect of the Animal Life of Equatorial Forests--Diurnal Lepidoptera or Butterflies--Peculiar Habits of Tropical Butterflies--Ants, Wasps, and Bees--Ants--Special Relations between Ants and Vegetation--Wasps and Bees--Orthoptera and other Insects--Beetles--Wingless Insects--General Observations on Tropical Insects--Birds--Parrots--Pigeons--Picariæ--Cuckoos--Trogons, Barbets, Toucans and Hornbills--Passeres--Reptiles and Amphibia--Lizards--Snakes--Frogs and Toads--Mammalia--Monkeys--Bats--Summary of the Aspects of Animal Life in the Tropics _pages 69-123_ IV. Humming-Birds: as Illustrating the Luxuriance of Tropical Nature. Structure--Colours and Ornaments--Descriptive Names--The Motions and Habits of Humming-Birds--Display of Ornaments by the Male--Food--Geographical Distribution and Variation--Humming-Birds of Juan Fernandez as illustrating Variation and Natural Selection--The Relations and Affinities of Humming-Birds--How to Determine Doubtful Affinities--Resemblances of Swifts and Humming-Birds--Differences between Sun-Birds and Humming-Birds _pages 124-157_ V. The Colours of Animals and Sexual Selection.