COLOURS PRODUCED BY COURTSHIP 295 



that the female Emperor was very different from the 

 inert creature I have described. In the full posses- 

 sion of her faculties, she doubtless took that intelligent 

 interest in courtship which is to ba expected of every 

 properly endowed female. 



I have also maintained that under these circum- 

 stances the colours are likely to disappear. Such a 

 conclusion can be tested by examining other species 

 in which the degeneration of the female is more 

 complete, and has doubtless occupied a far longer 

 time. 



In another genus of Bombyces (Orgyia), some of 

 the females (of which the common Vapourer Moth is 

 an example) are far more degenerate. They never 

 leave the cocoon, but lay their eggs all over it ; their 

 antennae and wings are rudimentary. The male, on 

 the other hand, flies actively about and has enormously 

 developed antenna?. Success in courtship is almost 

 certainly a mere question of speed and keen scent. 1 

 In this case the male is very plainly coloured in 

 various shades of brown, but he still retains a trace 

 of his vanished beauty in a white spot in the centre 

 of each fore wing. An examination of the pupa shows 

 us that the female once possessed larger .wings and 

 more perfect sense organs. 



In Psyche and allied genera the change has pro- 



1 Mr. E. B. Titchener tells me that this is not always the case; 

 for a female in his possession refused the first male which arrived. 

 The usual experience with the Emperor Moth, &c., seems to indicate 

 that such an exception is very rare. 



