The HISTORY oh LNSEC TS 
In another excrefcence, I found a third fpecies 
of Worms, which were likewife without feet, 
and were twice as little as the former. Their 
head was formed almoft in the fame manner: 
but it was thicker, where it is joined to the tho- 
rax. I obferved alfo, two black fpots in the 
head, which probably were the eyes: thefe 
Vermicles changed their {kin alfo, and crept 
pretty quick. “Sometimes two of thefe are found 
in one tubercle; and they then live feparated by 
their excrements, as by a wall between them: 
this very thing I have likewife fometimes ob- 
ferved, when their tubercles touched each other. 
Thefe Vermicles or Worms, likewife feem to 
undergo their changes within the excrefcences ; 
but at this time, the excrefcence aflumes a rufty 
colour all over it. I have not yet diftinGly feen 
their change; becaufe they are not found to be 
very common. It muft be good fortune, if any 
one fhould happen to difcover the order, in which 
the limbs and parts of thofe animals increafe. 
I made thefe obfervations on the 28th of June. 
When thefe feetlefs Worms have undergone 
their tranfmutation, or the Caterpillars, which I 
have defcribed, have left their tubercles; fo that 
thefe are open. and empty, then various other 
little Worms with feet, vifit and hide themfelves 
in them, or caft their eggs there, in order after- 
wards to nourifh their young in thofe cells. The 
{maller Spiders alfo frequently betake themfelves 
to thefe warts on leaves, that they may lie in 
wait, and catch the leffer infects that pafs by, and 
when caught, feed on them. For the Willow- 
leaves feed an infinite number of very {mall in- 
fects ; fo that a whole treatife might be wrote on 
the different fpecies of minute infects that are 
found about thefe trees. 
83 
Among other infects, I found on thefe leaves 
a very {mall Cicada; which, as to its changes, 
and its manner of living, is altogether like the 
larger Cicade of France and Italy. Very fmall 
Caterpillars are likewife found there, affixing an 
oblong and gold-coloured web to the leaves; 
out of which fome remarkable fpecies of {mall 
Flies are ufually afterwards produced. When 
thofe Flies iffue out of their little cafes, they like- 
wife throw out of them an operculum or cover, 
which is exactly round, as I have related of the 
web of the Caterpillar, which I have defcribed 
before and delineated. . 
Among the little infects which come from 
without, into the tubercles, I have obferved a 
very fmall one, that was white, oblong, ‘Tab. 
XLIV. VII. and has very great vital ftrength. 
It had two black eyes, fituated in the lowetft re- 
gion of its head towards the thorax.: Out of 
the forepart of its head projected two antenna. 
It had fix legs, over which were feen four wings, 
enclofed in little knots. The body appeared to be 
divided into rings, This little animal was changed 
after wards in to a black oblong Fly, with wings as 
long as the body. But when this change hap- 
pened, the infect was not at all deprived of its 
motion; therefore it belongs to the fecond order 
of changes. The reafon why I defcribe it under 
the fourth order, confifts in this, that its change 
is inwardly perfected in a concealed manner in 
the hollow tubercles of the Willows. It is fo 
{mall, that it can hardly be delineated in its na- 
tural fize. One muft therefore firft know thofe 
different modes of changes, and what infects vifit 
the excrefcences of the Willows, before one 
can, without error, make experiments on this 
matter, 
A particular defcription of certain infe&ts, which live between the jicf and fecond 
coat of the Willow leaves, and are chauged into Beetles. 
ESIDES the tubercles hitherto delineated, 
which contain the Caterpillar before defcrib- 
ed, there is likewife another {pecies, Tab. XLIV. 
Fig. vir. of Worms without feet, obferved to 
lie between the outmoft and inmoft coat of the 
Willow leaves: thefe I fhall now defcribe, and 
delineate them magnified, but I fhall firft treat 
of the leaf itfelf. The Willow leaf, as I have 
obferved before, confifts of three coats; whereof 
the inmoft is the moft fucculent; and may there- 
fore ferve many infects which eat the entire leaf 
for their proper food: but the Vermicles whereof 
I now treat, eat only the inmoft part of the 
leaf, leaving the inward and outward coat en- 
tirely untouched: they do not indeed devour the 
little nerves of the inward flefhy fubftance, but 
only the matter in their inteftines. Since thefe 
Worms therefore confumed only the middle of 
the Willow leaf, hence it is, that they are al- 
ways found lying immediately under the inmoft 
coat of that leaf; for this they eat and confume 
by degrees on the infide, until they come to the 
external coat, which very {trongly fupports the 
nervous filaments of the leaf. Thus at length it 
happens, that the infide of the Willow leaf is 
hollow underneath, and becomes feparated from 
the external: this is the reafon alfo, why the 
two coats of this leaf grow dry in that part, and 
affume a rufty colour: and this thews plainly, 
that the little animal lies between thefe two coats. 
I fometimes have found feventeen fuach Worms 
in one Willow leaf, which then indeed appeared 
to be divided into fo many rufty coloured {pots 
In order to underftand thefe matters more clear- 
ly, I have judged it proper to. reprefent two of 
thefe {pots in the natural fize; whereof the one 
is Clofed, and the other open, Tab. XLIV. Fig. 
1.2%. Inthe open {pot, it may be obferved, that 
the inmoft coat of the leaf is entirely removed 
from the middle larger nerve. It likewife ap~ 
pears there, that the {maller nerves of the one 
fide, are entirely naked, and the matter that had 
filled their interftices is confumed. In the op- 
pofite fide, befides fome excrement, there is feen 
the naked head of the Worm, together with the 
body, tranfparent through the elevated coat. 
That what has been hitherto faid, as well as 
the method whereby the Worms performs all 
thefe matters, may be more clearly. compre- 
hended ; I fhall now delineate the infec it(elf 
i} age 
