( ) 
II. A Letter from Mr Anthony van Leuwen- 
hoek, F. K. S. concerning Jome Inje£ls ob^ 
ferved by him him on Fruip Ireeu 
Delft, Oftob. 26. 1700. 
MY lad was of the 7th of the laft month, which I 
hope is come fafe to your hands 3 I take the li- 
berty again of fending you thefe my poor Obfervati- 
ons, with the Figures annexed. 
We have nor for many years obferv'd about this 
Town the Fruit-trees more loaden with Bloflbms than 
this laft Spring, nor at the fame time more cover'd 
with a fort of Black Flies, which appeared to me leffer 
than thofe of tormer years. 
This induced me to take fome of the Leaves of the 
Trees, and fome of the BlofToms of a Quince Tree, 
that had a great many of thofe Black Flies upon them, 
and put them, into a Glafs Tubejn order to make my 
obfervations of them, and the rather becaufe many 
were of opinion, that from the Eggs of thefe Flies 
would proceed fuch a great number of little 
Worms or Maggot s\ as would deftroy all the Fruit on 
the Trees. 
I obferved that thofe Flies would not live above two 
days, and that fome of them had laid a great number 
of longifli Eggs. 
The reafon why they liv'd no longer, I thought 
might be the want of Food, therefore I was refolved 
to obferve what the Flies did, as they fat upon the 
Leaves of the Plumb-trees, and found chat they had in- 
finuated thernfelvesinto the curFd leaves of the Trees. 
L 1 1 11 ' The 
