xii CONTENTS. 



IV. HuMMING-BlRDS : 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 Humrning-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 124157 



V. THE COLOURS OF ANIMALS AND SEXUAL SELECTION. 



General Phenomena of Colour Theory of Heat and Light as producing 

 Colour Changes of Colour in Animals produced by Coloured Light 

 Classification of Organic Colours Protective Colours Warning Colours 

 Sexual Colours Typical Colours The Nature of Colour How Animal 

 Colours are Produced Colour a Normal Product of Organization Theory 

 of Protective Colours Theory of Warning Colours Imitative Warning 

 Colours The Theory of Mimicry Theory of Sexual Colours Colour 

 as a Means of Recognition Colour proportionate to Integumentary 

 Development Selection by Females not a Cause of Colour Probable Use 

 of the Horns of Beetles Cause of the greater Brilliancy of some Female 

 Insects Origin of the Ornamental Plumage of Male Birds Theory of 

 the Display of Ornaments by Males Natural Selection as neutralizing 

 Sexual Selection Greater Brilliancy of some Female Birds Colour- 

 development as illustrated by Humming-Birds Theory of Typical Colours 

 Local Causes of Colour-development Summary on Colour-development 

 in Animals Concluding Remarks on Causes of Bright Colour in the 

 Tropics pages 158220 



VI. THE COLOURS OF PLANTS AND THE ORIGIN OF THE COLOUR-SENSE. 



Source of Colouring-matter in Plants Protective Coloration and Mimicry 

 in Plants Attractive Colours of Fruits Protective Colours of Fruits 

 Seeds how Protected Attractive Colours of Flowers Attractive Odours 

 in Flowers Attractive Grouping in Flowers Why Alpine Flowers are so 

 Beautiful Why Allied Species of Flowers differ in Size and Beauty 

 Absence of Colours in Wind-fertilized Flowers The same Theory of 

 Colour applicable to Animals and Plants Relation of the Colours of 

 Flowers and their Geographical Distribution Recent Views as to the 

 Direct Action of Light on the Colours of Flowers and Fruits Concluding 

 Remarks on the Importance of Colour in the Organic World THE ORIGIN 

 OF THE COLOUR-SENSE. Supposed Increase of Colour-perception within 

 the Historical Period Concluding Remarks on the Colour-sense 



pzges 221218 



