COURTSHIP AMONG ANIMALS 13 



constantly asserting that " Katy-did, oh-she-did, 

 Katy-did !" These are called katydids. What she 

 did, is a secret they keep to themselves. The female 

 only replies by a sharp chirp made by an upward 

 jerk of the wings. Does she confirm the fact that 

 " Katy did " or does she deny it ? 



The most beautiful of all the insects are the butter- 

 flies and moths. Their colourings and markings are 

 exquisite and extensively varied. The delicacy of 

 their wings is remarkable. When butterflies flutter 

 about in the sunlight, they show off their gorgeousness 

 to the best advantage. Darwin thought that this 

 beauty is due to Sexual Selection that is, that the 

 finest specimens of the males are chosen for mating. 

 But it is doubted now whether female butterflies 

 notice or are, in any case, able to appreciate the bright 

 colourings and intricate markings of the males, and 

 this would be necessary for a choice to be made. In 

 many cases the female, too, may be brilliantly coloured 

 and yet be completely different from the male. It 

 has been discovered that the males of butterflies 

 exhale a delicate perfume, which makes the females 

 aware of their presence, sometimes from a long dis- 

 tance. In the moths, however, the female is often 

 wingless and is consequently unable to move about; 

 here it is she that exhales the odour to attract the 

 male. Experiments have been made by a naturalist, 

 who took off the wings of some female butterflies and 

 placed them on the male. He also dyed some in 

 various colours, but found that these changes made 

 no difference in the choice of the females, thus 

 proving that it is not colour which is the source of 

 attraction. 



