Mi c r o s c op i c a l Essays. 



m the honey while the aphides are in the aft of difcharging 

 .the bees only colleft it from the leaves on which it has fallen. • 



In the autumn three more generations of aphides are produced, 

 two of which generally make their appearance in the month of 

 Auguft, and the third before the middle of September. The two 

 firft differ in no refpecl from thofe which are found in fummer : 

 but the third differs greatly from all the reft. Though all the 

 aphides which have hitherto appeared were females, in this tenth 

 .generation feveral male infe&s are found, but not by any 

 means fo numerous as the females. 



The females have at firft the fame appearance with thofe of 

 the former generations, but in a few days their colour changes 

 from a green to a yellow, which is gradually converted into an 

 orange before they come to their full growth ; they differ alfo 

 ki another refpecl: from thofe which occur in fummer, for all 

 thefe yellow females are without wings. The male infe&s are 

 however, ffill more remarkable, their outward appearance readily 

 diftinguifhing them from this and all other generations. When 

 firft produced, they are not of a green colour like the reft, but of 

 a reddifh brown, and have afterwards a dark line along the back ; 

 they come to their full growth in about three weeks, and then caft 

 off their laft covering, the whole infect being after this of a bright 

 yellow colour, the wings only excepted ; but after this change to 

 a deeper yellow, and in a very few hours to a dark brown, if we 

 except the body, which is fomething lighter coloured, and has a 

 reddifh caft. The males no fooner come to maturity than they 

 copulate with the females, who in a day or two after their inter- 

 courfe with the males lay their eggs, generally near the buds. 



Where 



