Microscopical Essays. 233 



the furface thereof. This aclion can only be effe&ed at intervals, 

 becaufe after each ejaculation the infe6t. is obliged to take a frefh 

 fupply of water. The larva will fometimes turn it's tail above the 

 furface of the water, and force out a fmall ftream from it, as from 

 a little fountain, and with confiderable force. 



The pupa differs but very little from the larva; the bunches, 

 containing the wings, grow large, and begin to appear like four 

 fhort thick wings. It is full as lively as the larva, feeking and 

 enjoying it's food in the fame manner : when it is arrived at it s 

 full growth, and is nearly ready to go .through it's laft change, 

 it approaches the edge of the water, or comes entirely out of it, 

 fixing itfelf firmly to lb me piece of wood or other fubftance by 

 it's acute claws. It remains for fome time immoveable ; the fkin 

 then opens down the back, and on the head ; through this open- 

 ing they exhibit the real head and eyes, and at length the legs ; 

 it then creeps forward by degrees, drawing it's wings, and then 

 the body, out of the fkin. The wings, which are moift and folded, 

 now expand themfelves to their real fize • the body is alfo ex- 

 tended till it has gained it's proper dimenfions, which extenfion 

 is accompliihed by the propelling force of the circulating fluids. 

 When the wings antl limbs are dry, it enters on a more noble 

 {late of life, it now wings the air and feeks it's mate. 



• ~ What terms expreflive may relate 



The change, the fplendor of their new-form cl ft ate ! 

 In ev'ry eye ten thoufand brilliants blaze, 

 And living pearls the vail horizon gaze : 



Ff 



Gem mo 



