( ^^t ) 



drawing as far as his eye could diftinguifli them, but at length they 

 became lb minute, and fo intermixed one with another, that no 

 true judgment could be formed of them. 



In S T V, are fhewn a few of the feathers, which fo exa6tly cover 

 both fides of the membrane, that no part of it can be feen. W W 

 W, are three larger feathers which were placed on the edges of the 

 wing. XXXXX indicate the membrane, when it was laid bare of its 

 feathers, on both fides, in order to difcover the blood-vcflels. And 

 here, though not in regular order, may be ^een the cavities or holes 

 in which the quills were fixed, and from which ihey had their origin. 



Farther, I confidered with myfelf, whether or no the blood-vefiels 

 confifted of arteries and veins ; but I could not fee any other than 

 one fort of veflels in the wings of all the infe6ts of this fpecie^, which 

 I have examined, except that once I thought I faw in the thinneft 

 part of the v/ing of a grafshopper, that in the larger vefiels next the 

 body, another fpecies of veflels vvas inferted. 



The conclufion drawn by me upon the whole'was, that there was 

 not any circulation of the blood in the wings of tliefe creatures, and 

 that the blood-venels I have been defcribing, which certainly were 

 arteries, were only defigned to perfe(51: the formation of the wing with 

 its multitudes of feathers, and afterwards, to convey the blood, with 

 an exceeding flow motion, through the veflels, in order to afford a 

 fmall degree of fupport to the wing in its perfe6t ftate. For, as 

 thefe butterflies, and thole Avhich are produced from the filk-worm, 

 and many other flying infedls which proceed from caterpillars, do 

 not take any food, and do not live any longer than till they have 

 coupled and laid their eggs, it is not neceflbry, in my opinion, that 

 the blood in their wings fliould have any circulating or retrograde 

 motion, and befides, the membranes being of a fiift' horny nature, 

 they require little or no nourifliment. 



I cannot here omit to mention, that I have heretofore often taken 



