228 THE COURTSHIP OF ANIMALS 



of a giant measuring two feet in expanse of wings has 

 been found in the Carboniferous. This species, however, 

 seems to have stood near the parting of the ways between 

 the May-flies and the Dragon-flies. But be this as it 

 may, undoubtedly Dragon-flies hovered over the backs of 

 sleeping Ichthyosaurs and furnished food for Pterodactyles 

 millions of years ago, as they now hover over lazy kine 

 for the sake of the flies forgathered there, or dodge to 

 avoid the stoop of the Hobby, and in all this vast space of 

 time they have not appreciably changed. 



And what is true of the Dragon-fly is true also of the 

 May-fly, for it is clear that they are of the same stock. 

 It is true at any rate in so far as the conformation of 

 the body is concerned. The possibility that it may be 

 equally true in regard to the details of their life-history 

 almost staggers one, because these are, in many respects, 

 of a quite remarkable character. As with the Dragon- 

 fly, there is a prolonged period of larval life, lasting from 

 one to two years, which time is passed in streams and 

 pools where a luxuriant vegetation ensures a plentiful 

 supply of food. Some are carnivorous, but in the majority 

 of species minute plants only are eaten. More than forty 

 species are to be reckoned as natives of the British 

 Islands, the commonest being the " Green Drake " and 

 " Grey Drake," beloved by the fisherman. These names 

 are applied, it may be mentioned, to the phase known as 

 the sub-imago which precedes the fully-adult stage, of 

 Ephemera vulgata and E. danica. 



Save that it is curious that while the larvae of some 

 species are carnivorous those of others are vegetarians, 

 there is nothing very remarkable about what may be 

 called the infantile period. But when this is ended the 

 span of life remaining to them as adults is brief indeed. 



