68 PLATE XXXI. 



of a moft fingular ftrufture* This happens about the latter end of 

 May^ or beginning of June^ if the weather proves favourable ; they 

 will then be found in fliallow ftanding w^aters, crawling on the grafs or 

 plants ■w^iich grow there, or they may be taken floating on the furface 

 of the water. The Body confifts of twelve annular divifions, whereof 

 the Head and Tail are two ; the Tail has a verge of hairs, which, 

 when entirely expanded, fupport the creature on the furface, with its 

 head downwards. If it wifties to defcend, it contracts the hairs in the 

 form of a wine glafs, or entirely clofes them at the end ; and when 

 again it is rifmg to the furface, it forces a bubble from a fmall aperture 

 in the center, which immediately makes a paflage for its afcenfion. — 

 It changes to the Pupa ftate, and about the middle of July to the Fly. 

 It fubfifts at this time on the nedar and other juices it extra<Sls from 

 the bottom of the corolla in flowers* 



FIG; 



