The HOLST ORY of A NSP Guts. 
lated conftruétion, Tab. XLIV. Fig. xn a, 
and fituated in the head at a very little diftance 
from one another: under the eyes is feen a 
black, crooked {nout, full of little cavities, and 
of a fubftance between bone and horn 4, and 
on the forepart of the {nout are placed the teeth 
of this Beetle. The little horns are very difcer- 
nible, and are of the fame colour with the fkin 
of people who have been much expofed to the 
fun: they arife very gracefully from about the 
middle of the fnoutcc. They are each com- 
pofed of eight joints, and are fo thick at their 
ends, that they may very properly be called 
prepilata, or knobbed horns. ‘The thorax 
confifts of a very black horny bone, and is 
full of white hairs, and little cavities ; from 
the lower part of it arife fix lees ddd; they 
ate of a moderate thicknefs, but flenderer at 
their extremities. Thefe legs are covered with 
-hairs, and with little irregular eminencies ; in 
colour they refemble the horns. Each leg con- 
fifts of fix joints, and each foot of four, of 
which the laft are armed with two nails. The 
fecond joints of the two hinder feet are fome- 
85 
what blackifh, and much thicker in propor- 
tion, than the fame joints in the fore legs. 
The reafon of this difference feems to be, 
that the former contain fome very ftrong muf- 
cles, by means of which this infe&t can {pring 
on its hinder feet in the fame manner as Flies, 
but fomewhat flower. I faw one of them 
make a leap of three inches and a half, which is 
about twenty-eight times the length of the crea- 
ture’s body. . The cafes of the wings are like- 
wife black ee, but covered with a fine white 
down, and are furrounded with a {mall bor- 
der; they are alfo ribbed, and full of cavities ; 
notwithftanding which, they fhine like the beft 
polithed looking-glafs. The wings are meni- 
branaceous, and twice as long as the cafes, fo 
that to defend them, they muft be folded 
up, which they accordingly do in a moft ex- 
quifite contrivance. Tho’ I could eafily pro- 
cure infects enough of this kind, I could not 
find time to diffecét them; for which reafon I 
have nothing to fay of their eggs, or of their 
genital, and other internal parts. 
An account of fome finall Worms that are bred within the new and tender leaves 
of Willows, and afterwards change to Flies. 
N the twenty-eighth of June I obferved, 
in looking over fome Willows, that fome 
of their young leaves, which had but juft 
made their appearance about the tops of the 
branches, began already to dry up and wither, 
Tab. XLIV. Fig. x1v.a. This was enough to 
engage my curiofity; and accordingly, 1 im- 
mediately fet myfelf to difcover the reafon of 
fo fudden a decay. On feparating thefe wi- 
thered leaves from one another, I found be- 
tween them many collections of living Worms, 
to the number of eighteen or twenty together 4, 
and as it were, in the moft friendly and fociable 
manner. Thefe infects were of an oblong 
figure, but fomewhat broader in the middle 
than at the extremities, and of a moft delight- 
ful bright orange or faffron colour. Some of 
them had already begun to make their webs, 
and others were employed in preparing them- 
felves-for it. 
On this difcovery I fearched fome other new 
leaves, and found in them a great variety of 
Worms of the fame fpecies, fome more grown 
than others. I found alfo in fome of the leaves 
the eggs from which thefe Worms had been 
hatched; but they were lodged only between 
the folds of the leaves, and not within their 
fubftance, as was the cafe in the lat obferva- 
tion. 
Thefe Worms lived merely upon the juices 
flowing from the leaves where I found them ; 
but as this juice is very tough or vifcous, it may 
naturally contain fufficient nourifhment for 
them, and fo render unneceflary their preying 
on the fubftance of the leaf itfelf Whether 
this juice flowed {pontaneouily from the leaves, 
or whether they made incifions in them to ex- 
tract it, is a thing which I cannot take upon 
me to determine. I never faw any of thefe 
Worms ftir from under the folds, and wrin- 
kles of the leaves, but obferved, that they con- 
ftantly crawled under cover, from one cavity to 
another, till they had attained their full growth, 
and the embryo limbs contained under their 
fkins, were arrived, by the due degrees, at a 
proper fize, to prepare for their fucceeding 
appearance. 
When the leaves, whofe greennefs and 
growth is deftroyed by thefe Worms, begin 
to harden and dry up, the Worms, without 
ftirring from under cover, form themfelves 
webs, in which they at length become Nymphs. 
They make their webs ftronger and thicker 
about the head and thorax, than elfewhere, as 
thefe parts are to be the chief {cene of the en- 
fuing changes, and of the growth of new 
limbs ; and therefore require an extraordinary 
bulwark to defend them, efpecially as the 
leaves about this time grow very hard and 
rugged, and therefore more apt to crufh, and 
otherwife hurt the enclofed infects. As thefe 
communities of Worms live under one cover, 
and in a kind of brotherly ftate, on the fame 
{pot, they form their webs one clofe to another, 
without any difturbance and encroachment one 
on another. 
The Nymph of this Worm is very fmall, 
but it exhibits, notwithftanding in its parts, the 
figure of the future Fly. It lofes all: manner 
of fenfible motion, except in the tail, which it 
is {till able to ftir with great violence. On the 
fourth of July, I obferved that thefe infeats were 
turned to Flies, which appeared through the 
microfcope, of a mioft delicate conftruction, 
Tab, XLIV. Fig. xv. The head refembling 
that of a pin, was joined to the thorax by a 
very 
