‘Teh The BOOK of 
is likewife fhewn here ¢, appearing like a black- 
ith triangular fpot. We may likewife diftin- 
guifh by the.microfcope feven other little parts 
of the mouth, whereof I exhibit three, as well 
above the mouth as at its fides; but the feventh, 
which is fomewhat brown, is obferved to have 
its two bafes placed near the thorax, and reach- 
ing to the eyes. This little part is fomewhat 
whiter in the middle, and grows browner a little 
lower near the mouth, but in the anterior or 
fore part, it appears to be formed like the nails 
of our fingers, or the {cales of fifth. Where this 
little part terminates with its brown curvature 
or winding, almoft in the middle or lower re- 
zion of the head, I exhibit the firft of the 
three pair of little parts already named. This 
pair is of a triangular figure, on account of the 
hairs wherewith their inner fide is furrounded. 
About the end of this follows another pair of 
the like little parts, the beginning of which are 
horny or bony, but the extremities are hairy. 
Below thefe again are feen a third pair of little 
parts which are fomewhat thicker and more 
fhaggy, and extend) to the hairs of the horns. 
Thefe three pair of little parts are, properly 
peaking, articulated briftly hairs, which the 
Worm of the Gnat makes ufe of to direct the 
food to its mouth. I have before obferved 
fomething like this in the hermit Crab, in 
which I have defcribed many little parts of a 
fomewhat like kind. The mouth of this 
Worm is in the fore part befet thickly with 
hairs, which are all of equal length, and are 
placed equally diftant from one another: this 
is fhewn at the letter c. 
In the thorax are certain regular divifions dd, 
which are produced by the growing and extu- 
berant joints of the legs and wings of the Gnat 
within. Hence I can fhew even in this Worm 
all the limbs and parts of the future Nymph, 
and of the perfect Gnat lying under the skin, 
as I fhall do on a fucceeding occafion in the 
Worms of Bees, and fhall thus exhibit an ex- 
ample applicable to all other infects belonging 
to this firft {pecies, or method of the third order 
of natural transformations. Afterwards, when 
I come to the fecond method of the third or- 
der, I thall prefent to the eye.a kind of. fimilar 
inftance on the diurnal Butterfly. We may like- 
wife further obferve how the thorax of this 
Worm is diftinguifhed .with furrowed lines, 
and befet on each fide with briftly hairs, many 
iffuing together as it were out of one center. 
The belly is divided into eight annular fec- 
tions, Tab. XX XI. fig. v. ee; to which, if you 
add the fhaggy extremity fof the tail, and that 
part of it which is likewife ftrengthened g with 
the briftly hairs, and is. extended by the 
‘Worm above the furface of the water, ten 
rings muft be reckoned in the whole. In that 
part of the tail which is feen b above the fur- 
face of the water, there appear certain black 
fpots, and fome depreffions or holes, as alfo 
many briftly hairs. But here we moft take 
particular notice, that whenever the Worm, 
{wimming in the middle of the water pulls 
NPA? I’ G@ RIB: Son, 
down the part of the tail juft mentioned undef 
the water, that part never becomes wet. ‘There- 
fore, when the Worm wants to reft, or ceafe 
moving, it immediately goesup to the furface, 
and there, by means of its-tail, fufpends itfelf 
almoft in the fame manner as we fee a little. 
glafs figure of aman hang pendulous in a glafiy 
bubble in water. This is done-the eafier by 
this Worm, becaufe its tail always remains 
dry: hence it is alfo obferved that as foon as 
this appendage of the tail has again emerged to 
the furface, the water immediately fows away 
from it on every fide. And one may diftinctly 
fee that a kind of bafon or hole is by that means 
impreffed on the water, when the body of the 
Worm gravitates downwards; the water not 
being able to penetrate into the dry tail and its 
depreffions, is {topt in its circumference : and 
therefore the Worm, in regard to the extremity 
of its tail, very beautifully fwims in the water 
in the manner of an empty hollow glafs. The 
like effect may be likewife produced by art, 
if a needle be drawn through a cork and put 
into the water; for the cork will then {wim on 
the water, and in like manner make a confi- 
derable depreffion in the furface. 
Near the extremity of this tail I exhibit 
fome bubbles in the water z; thefe are fre- 
quently feen, and they arife from the air which 
the Worm can at pleafure emit there out of its 
body. I have feen that the Worm, in order 
to draw in the air, has raifed its head out of 
the water. When it has happened that the tail 
had loft its drynefs, and the Worm by this means 
can no longer fufpend itfelf on the furface of 
the water, which is the cafe when it is bruifed 
or handled too roughly ; I have ‘on thefe oc- 
cafionsobferved, that it put its tail in its mouth, 
and afterwards drew it back together with its 
hairs. In this method of proceeding the infect 
refembles water fowls, which, by drawing their 
quills through their beak, prepare them in fuch 
a manner that they can refift the water. They ~ 
fecrete this fat matter by means’ of a double 
gland which they have in their rump, in which 
this oil, which ftrengthens’ the wings againft 
the water, is generated and excreted, and they 
thence take it into their beaks. I have fome- 
times covered anatomical inftruments of fteel 
with this matter, in order to keep them from 
rufting, and have found that the fteel continued 
perfectly defended from ruft by means of it; and 
I think it would have greater effect, if one hada 
great quantity of it boiled and properly ma- 
naged. 
As this whole infe@t is pellucid, I have here 
exhibited the two tranfparent pulmonary tubes 
which appear in the middle of the tail where 
it floats in the water. Thefe arife from the 
body near the thorax, and contain, ‘T ab. XX XT. 
fic. v. £2, in them the quantity of air whereby 
the bubbles are produced. This infect there- 
fore breathes at its tail, in the fame manner as 
the Worm of the Gad Fly. But this tail is not 
fo abfolutely neceffary for the Worm of the 
Gnat, that it cannot live without it. It only 
ferves 
