Introduction. 5 



Protection is ensured in many ways, and among insects one of 

 the commonest has been the acquisition of a nauseous flavour. 

 This is often apparent even to our grosser senses ; and the young 

 naturalist who captures his first crimson-and-green Burnet Moth or 

 Scarlet Tiger, becomes at once aware of the existence of a fetid 

 greasy secretion. This the insectivorous birds know so well that 

 not one will ever eat such insects. But unless there were some 

 outward and visible sign of this inward and sickening taste, it 

 would little avail the insect to be first killed and then rejected. 

 Hence these warning colours they as effectively signal danger as 

 the red and green lamps on our railways. 



It may here be remarked that wherever mimickry occurs in 

 insects, the species mimicked is always an uneatable one, and the 

 mimicker a palatable morsel. It is nature's way of writing " poison " 

 on her jam-pots. 



The other class of prominent colours the Sexual have given 

 rise to two important theories, the one by Darwin, the counter- 

 theory by Wallace. 



Darwin's theory of Sexual Selection is briefly this : He points 

 out in much detail how the male is generally the most powerful, 

 the most aggressive, the most ardent, and therefore the wooer, 

 while the female is, as a rule, gentler, smaller, and is wooed or 

 courted. He brings forward an enormous mass of well-weighed 

 facts to show, for example, how often the males display their 

 plumes and beauties before their loves in the pairing season, and 

 his work is a long exposition of the truth that Tennyson proclaimed 

 when he wrote : 



" In the spring a fuller crimson comes upon the robin's breast, 

 In the spring the wanton lapwing gets himself another crest, 

 In the spring a livelier iris changes on the burnished dove, 

 In the spring the young man's fancy lightly turns to thoughts of love." 



That birds are eminently capable of appreciating beauty is 

 certain, and numerous illustrations are familiar to everyone. Suffice 

 it here to notice the pretty Bower Birds of Australia, that adorn 

 their love arbours with bright shells and flowers, and show as 

 unmistakable a delight in them as the connoisseur among his art 

 treasures. 



From these and kindred facts Darwin draws the conclusion 

 that the females are most charmed with, and select the most 



