( io8 ) 



to me, tlicit all thefe green globules were contained in a thin tranfpa- 

 rent fluid. 



From thefe obfervations I concluded, that tlie tranfparent mem- 

 branes which principally conftitute the wings of thefe fmall animals, 

 are as completely provided with blood-velTels, finews, &c. as the 

 bodies of other creatures. 



I formerly was of opinion, that in the wings of thefe fmall flying 

 treatures tliere was no circulation of the blood, for I judged, that in 

 its paffage through fuch exceeding flender vell'els, it mull be evapo- 

 rated or dried up : and the rather, as many of thefe winged infG(51:s do 

 not take any food, but only live a few days, and die as ibon as they 

 have coupled, and laid their eggs. But if we recolle6l, that the mem- 

 branes of their wings are of a hard and horny nature, though exceed- 

 ing thin, we may conclude, that all the vefl'els, compofmg this liorny 

 membrane are fo firm and tough, that, though all the fluid con- 

 tained in them fhould be dried up by the heat of the fun, the vell'els 

 thcmfelves would not coUapfe or flirink up, as thofe in our own 

 bodies, or the bodies of other animals would do in the like cafe. 



I was confirmed in this opinion, by obfcrving that the blood-vef- 

 fels in the wings of thefe infe61:s were not of the fame make as thofe 

 in the bodies of the human fpecies and of terreftrial animals, but were 

 compofed of annular parts, or rings, like the windpipe and the vefiels 

 pertaining to refpiration in tiie lungs of animals. And, though we 

 may not be able to difcover ^ill thefe velTels in the wings of infefts, 

 yet we may be afllired that tliere is an incredible number of them 

 entering into tlie compofition of thofe wings. And, fliould we ima- 

 gine, that thefe vcllels by reafon of their fmallnefs or their hard and 

 dry nature, are impervious to blood and juices for the fuflenance of 

 the wing, we mull confider that there is not a fingle hair or feather, 

 how fmall foever it be, which is found upon one of thefe wings, but 

 muft have had in it many fmall vefiels neceilar}' for its produ6lion ; 

 for every feather has its quill and every quill mufl have a great iium- 



