C *87 ’] 
duced in May, which twice cads off its covering ^ 
•while the months of June and July each fupply 
two more, which caff off their coverings three or 
four times, according to the different warmth of 
the feafon. This frequent change of the outward 
covering is the more extraordinary, as it is the ofteneft 
repeated when the infedls come the fooneft to their 
growth ; which I have fometimes obferved to hap- 
pen in ten days, where warmth and plenty of 
nourifliment have mutually confpired. From which 
confiderations, I am thoroughly convinced, that thefe 
various coverings are not connate with the infedl ; 
but that they are like, the fcarf-fkin, fucceffively pro- 
duced. 
Early in the month of June, fome of the third 
generation, which were produced about the middle 
of May, after cafting off their laft covering, difcover 
four ercdl wings, much longer than their bodies: 
and the fame is obfervable in all the fuceeding gene- 
rations, which are produced during the lummer 
months j without however diftinguifhing any diver- 
fity of fex, as is ufual in feveral other kinds of in- 
feds. For fome time before the Aphides come to 
their full growth, it is eafy to dilcover which of 
them will have wings, by a remarkable fulnefs in 
the bread:, which in the others is hardly to be didin- 
guidied from the body. When the lad covering is 
rejeded, the wings, which were before folded up in 
a very narrow compafs, gradually extend themfelves 
in a mod furprizing manner, till their dimenfions are 
at lad very confiderable. But thefe winged ones 
have this further peculiarity, that the number of 
them does not feem fo much to depend on their 
B b 2 original 
