158 PROBLEMS OF EVOLUTION 



At the end of it all it sometimes happens that she is not charmed, 

 and devours her little suitor ! Are we, like de Geer when he 

 saw this catastrophe, to be " filled with horror and indignation," 

 or are we to laugh ? At any rate all will agree that it is a fine 

 system for selecting the boldest and most vigorous males. 



It is among spiders that we first find a power of making 

 sounds, which, limited as it is to the males, we may consider to 

 have been developed in connection with sex. It is a stridulating 

 noise produced by rubbing a ridge at the base of the abdomen 

 against the hinder part of the thorax and is much feebler than 

 the music which insects make by similar means. 



There is no need to say much about insect musicians. They 

 include crickets, bees and grasshoppers. As a rule the notes 

 emanate from the male alone, and there can be little doubt that 

 their object is to call the female. The song of the cicadas has 

 charms for Chinamen who keep them as pets, but in Brazilian 

 forests, where the whole air rings with the din, it is the fair sex 

 of the species who are being serenaded. Among the insects that 

 are not musicians many have wonderful adornments that are 

 more striking in the males, if not peculiar to them. Among 

 these decorations are to be included the enormous horns of some 

 species of beetles, for apparently they never fight with them. 

 But pugnacious insects are not wanting. Male field-crickets are 

 great fighters, and the Chinese, at once so ancient and so childish, 

 "keep them in little bamboo cages, and match them like game 

 cocks." l Male stag beetles what else could their enormous 

 mandibles be for ? have great battles among one another. 



In all the five classes of vertebrates fishes, amphibians, 

 reptiles, birds and mammals we find secondary sex characters. 

 The male stickleback (gasferosteus), all crimson and green, dances 

 round the female when he has driven her to his nest. The little 

 polygamist makes the eggs his peculiar care and defends them 

 against all comers, even his wives, who are apt to cast cannibal 

 eyes on their own offspring. Male salmon fight much among 

 one another and in some fish the male is far the more brilliant. 

 The male dragonet is so bright with blues and yellows that 



1 Darwin : Descent of Man, p. 360. 



