SOME "COLD-BLOODED'' LOVERS 163 



the efRcient working of the sexual instincts. In the 

 higher animals, the phenomena which these present are so 

 complex that they often assume something more than a 

 semblance of intelligent, purposeful behaviour. It is 

 therefore necessary, for their right understanding, that 

 they should be analysed in animals lower and lower in 

 the scale of life till at last we come to the very simplest 

 types of organisms wherein instinct can be said to play 

 a part. 



The lower we descend in the scale of animal life in our 

 survey of behaviour during the reproductive period, the 

 more the evidence seems to grow in favour of the inter- 

 pretation of the Sexual selection theory adopted in these 

 pages — the view that neither the formal displays nor the 

 exaggerations of colour and ornament which so commonly) 

 accompany them, are due to female choice ; a choice not 

 necessarily conscious, but rather to be interpreted as the 

 final abandonment to the finest performer of a number of 

 suitors. On the contrary, this ornamentation, of what- 

 ever kind, is the expression of an intensification of the 

 gland secretions which is manifested by the process of 

 pigment concentration and a consequent intensification 

 of coloration. Hand in hand with these developments 

 it would appear goes an exaggeration of the normal move- 

 ments which characterize the species when under the 

 influence of great excitement, whether of fear or pleasure. 

 At any rate, the displays of gaudily coloured and highly 

 ornamental species are commonly more striking than 

 those of sober hue. 



On this rendering, the behaviour of Reptiles, Amphibia 

 and Fishes, is much more readily interpreted, and this is 

 even truer of the more lowly groups of animals such as 

 Spiders, Butterflies and Beetles. 



II* 



