294 THE COLOURS OF ANIMALS 



Disappearance of the beauty of males when the 

 females become degenerate 



I will now return to the Emperor Moth, and 

 attempt to show how its bright colours can be ex- 

 plained by the theory of Sexual Selection. In its 

 present condition the female is certainly passive, and 

 probably always accepts the attention of the first male 

 to arrive. The antennae, which are so wonderfully 

 complex in the males, are simple and rudimentary in 

 the female, and probably valueless as sense organs. 

 We must therefore believe that the conditions which 

 produced the bright colours and patterns are now at 

 an end, and that their disappearance is only a question 

 of time. And there is evidence for both these con- 

 clusions. 



If we examine the female chrysalis, the antennae 

 are seen to be large and well- formed, and altogether 

 out of proportion to the slender thread-like organs 

 which are formed within them. The antennae have 

 dwindled in the moth, but BO recently that the pupal 

 organs within which they are formed have undergone 

 but slight diminution, if any at all. This most inter- 

 esting fact was brought before my notice by Professor 

 Moseley. Here then we have the clearest evidence 



reach a safe conclusion. Professor Moseley's account is, however 

 supported by o. large number of observations upon other species, in 

 which the relation between the sexe resembles that obtaining in 

 Ornithoptera, 



