EPHEMERA MARGINATA. 69 



minutes, where it casts off from its wings the last pel- 

 licle, which is a thin and delicate membrane, formed 

 under the elytra of the crysalis. It then appears in the 

 imago state, with its biforked tail and wings, as repre- 

 sented of the full size in figure 6. 



Having become a perfect Ephemera, it hovers about 

 in the air, the male and female generate, the latter drops 

 her eggs in the water, and both die, existing only a few 

 short hours, to perform all the offices destined for them 

 to fulfil in the economy of nature. 



So beautiful and perfect are the arrangements of the 

 Creator, in order to preserve a regular succession of his 

 creatures, that if the Ephemerae be kept from sexual 

 intercourse, I have known them live for several days. 

 Nor do they seem enfeebled when confined separately for 

 a week, as I have seen them fly away with great celerity 

 after that interval ; while others, which were bred the 

 same season, and were not kept separate, died after a 

 few hours' existence. 



