VARIETIES. 323 



the insect, which was rapidly followed by the head and 

 anterior legs. After this effort the insect rested a few seconds. 

 The next discernible motion was in the two or three last 

 segments of the abdomen, where the muscles were in violent 

 agitation, evidently for the purpose of extricating the fine setce 

 which adorn that part. The contractions continued upward ; 

 and the wings, freed from their flimsy covering, were fully 

 developed, and in an instant the delivered captive took its 

 flight: the whole process strongly resembling the drawing off 

 of a tight glove. The whole operation did not, in most cases, 

 exceed three minutes ; in some cases less. Scarcely an instant 

 elapsed between the full development of the insect and its taking 

 flight : so rapidly did they acquire consistency. In some few 

 instances I observed them coupled, in which case they soon 

 died. I made a dozen or so find their way into a phial ; they 

 instantly deposited their eggs and died : one only, which I 

 believe was a male, survived when I reached home, less than 

 one hour after. 



The number of the insect was truly surprising : they covered 

 every part of my apparel, and my face and hands were not 

 exempt. On my arrival at home my hat looked like a miller's, 

 from being completely covered with the ejeavice. I had taken 

 several of these insects during the evening, and had put them 

 into pill-boxes; almost all, however, were immature, and died 

 without undergoing their metamorphosis ; from which it would 

 appear, that light and a free atmosphere are essential to its 

 accomplishment. The principal swarm, however, appeared 

 about an hour before sunset, and, I presume, enjoyed their 

 hour's existence in one of the finest sunsets of this glorious 

 summer. 



The remarkable, and, I believe, peculiar habit, of the 

 Ephemerae to undergo a quadruple metamorphosis, deserves 

 more notice than it has obtained. The insect appears to 

 possess all the faculties of the perfect insect prior to this last 

 change : it is true it does not fly so readily, and it is apparently 

 of a more yielding matter : if disturbed in this state, although 

 inactive, they will escape. Can any of your correspondents 

 inform me as to the prior state of this tribe, and the characters 

 of the larvcs and pvpce ? 



A. H. Davis. 



Can he rtvell, A ugus / . 



