16 HALF-HOURS IK THE GREEN LANES. 



The tracheal or breathing system of the Ephemera 

 must be served in the same way, to obtain it as a 

 microscopical specimen. It is, however, much more 

 difficult to manipulate, on account of the fragility of 

 the leaflets. 



Space only allows brief reference to the surface 

 insects, the well-known Whirligig Beetles (Gyrinus 

 Fig. 39. Fig. 40. 



Larva of Ephemera, 

 b. Natural size. 



Larva of Dytiscus 



natator), to be seen going through their fantastic 

 quadrilles on the surface of every stagnant pool. 

 But these humble creatures have a fair geological 

 antiquity; for the Forest bed, cropping up from 

 beneath the glacial deposits of the Norfolk coasts, 

 shows that this same species was in existence long 

 before England became an island for the second time, 



