154 FOURTH DEVELOPMENT. 



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 

 singular process by which this additional and final change is 

 effected has been thus described. 1 



"After its release from the Puparium, and making use of 

 its wings for flight often to a considerable distance, the little 

 Ephemera fixes itself by its claws in a vertical position to 

 some convenient object, and withdraws every part of the body, 

 even legs and wings, from a thin pellicle which has enclosed 

 them like a glove the fingers, and so exactly do the exuvicBj 

 which remain attached to the spot where the Ephemera 

 has disrobed itself, retain their former figure, that I have 

 more than once at first eight mistaken them for the perfect 

 insect." 



When thus adorned in their best and what may properly be 

 called their bridal vestments, love and pleasure (unimpeded 

 even by the exigences of hunger, air being then their only 

 food) form the brief and brilliant consummation of their 

 lives. 



The seasons as well as hours of appearance vary with 

 different sorts of Ephemerae, which are not therefore strictly 

 May-flies. That figured in our plate is a large common 

 species, 2 which we have noticed late in May, and early in 

 June, sporting in groups of few or many, near the banks of 

 the New River at Hornsey. Its most usual hours of appearance 

 have been from seven till eleven in the morning, and from 

 about sunset until dusk. We may here observe, that confine- 

 ment, instead of abridging, would seem sometimes to prolong 

 the existence of this short-lived creature ; for of some of the 

 above species put into a box, at night, several were found 

 living in the morning. 



Some of these insects appear in England even as late as 



1 By Kirby and Spence. 2 Ephemera vvlgata. 



