The Leaves of thefe Plumbs,and of other FruiLTree? 
were covered with a great number of fmall Creatures, 
that are frequently found on the Leaves of Currant and 
Cherry-Trees, which fort of Creatures we here call 
Lice, fonie of them being Green; and others which 
are fometiraes lefs, and of another ftiape, blackiQi, and 
both forts in time become Flies. 
Having obferv'd this, I was thinking at firft, whe- 
ther thofe Flies above-mentioned did not come to the 
Trees, and particularly to the Plumb and Cherry-Trees 
only to get their Food, which I took to be thofe young 
Lice, which were there in vafl: numbers, and many of 
them no bigger than the fmalleft Sand, But look- 
ing more narrowly into the matter, it appeared clearly 
to me, that they did thefe little Creatures no harm, 
but came to lick up, as it were, with thofe Inftruments 
which they have on the fore- part of their Head, be- 
tween and about thofe little Creatures, als gifts en weder^ 
hach^ards and forwards^ themoifture that comes out of 
the Leaves, and that which comes out of the little 
holes, which thofe Lice with their inftruments alfo 
bore thro the Leaves, and from whence they extraft 
their nourifliment. - 
On the 20th of My/, I pluck'd four little Leaves off 
a Plumb-Tree, upon which were g6 of thofe Black 
Flies, befidcs fome hundreds of thofe little Creatures 
we call Lice, and amongft them feveral little ones that 
were newly come out of their Mothers Belly j all thefe 
with the Leaves I ftiut up in a Glafs Tube. ^^^'^ ^ 
Of the 36 Flies moft of them were Females anci had- 
their Eggs in them, except one that had laid hers a- 
gainft the fides of the Tube. 
Amongft thefe Flies I found two forts, with this 
difference, only that the Hoom VUefen^ wherein their 
Eyes are placed, were in fome of them four times as 
big as in others. 
Here 
