52 LARVA AND PUPA. 



which it is consequently always full. This cavernous abode 

 serves the double purpose of protecting it from the jaws of its 

 finny foes, and of providing it with a ready supply of that 

 slimy earth on which it is supposed chiefly to subsist.* It has 

 however been suggested that the insect may, after all, only derive 

 nutriment from the decaying vegetable matter mixed with the 

 ciirtli thus swallowed ; but that if, on the contrary, it really feeds 

 on earth, the fact would at once abolish the distinction laid 

 down by Mirbel between the animal and vegetable kingdoms. 



In the above sub-merged, subterranean, sunless and earth- 

 eating existence the streams of life and of its native current 

 glide for four and twenty successive moons over the head of 

 our as yet misnamed Ephemera, which, during the latter part 

 of the same period, exchanges the first (or Larva] for the 

 second (or PHJW) state of insect life. It is then that on some 

 fine May morning (or may be evening) it bids adieu for ever to 

 its dark subaqueous dwelling, and rises to the surface, prepared 

 to enter on its third estate. 



Having burst from the Pupa skin, which is left behind as 

 the badge and bandage of an inferior and confined condition, 

 it quits, in company with numerous fellows, the water for the 

 air, in the shape, to all appearance, of a perfect fly. As if, 

 however, the most fugacious of all insect forms was purposely 

 designed to be also the most elaborately finished, it has still to 

 pass through another and fourth stage of development. The 



: See Insect Architecture, p. 206. 



