The ‘B OVOIK tof 
mours, flowing out of the wounded cloaca, or 
liver, render every thing muddy; and, when 
thrown into the water, they likewife foul and 
deftroy its clearnefs. 
The double. ovary *, which appears of a 
whitifh aqueous colour in the young Nymph, 
is, in the more advanced ftate, of a pale yellow 
colour.. But if the Nymph is to change its 
{kin immediately, it-appears to be a beautiful 
green. In the region of the abdomen, where 
the ovary extends itfelf to the thorax, are feen 
two empty curled bags. They are the two 
pneumatic veficles, as I fhall fhew more at 
large in the hiftory of the parts of the perfect 
Fly. In the extremity of the body, between 
the laft rings, appear three very beautiful 
tranfparent knots; each of which, being fup- 
ported by its own footitalk, cafts a fkin, and 
difclofes itfelf, when wounded. What thefe 
little parts are, I cannot determine: Ihave dif- 
covered only, that they belong to the genital 
organs of the female; forI never faw them in 
the males, and therefore I fhall delineate them 
in the figure of the latter. 
The male part, at the fame period of ma- 
turity, became by degrees confpicuous ; and, 
from a thin aqueous humour, having acquired 
fufficient frmnefs, they had obtained a limpid 
and pellucid whitenefs. ‘The mufcles in the 
breaft are at this time much more compact, 
and, from a pale white, become of a purplifh 
colour. In the young Nymph they were foft, 
mucous, and like veal-jelly, and had no firm- 
nefs. 
But much more remarkable than thefe are 
thofe changes, which, by a flow accretion of 
parts, are feen in the head, eyes, pulmonary 
tubes, and fat, which may be feen there ina 
very abundant quantity; and alfo in the horny 
little bones, which firft confifted only of hu- 
mours,.as it were, and membranes. But I 
now pafs thefe things by, without further no- 
tice, becaufe I fhall hereafter make mention of 
fome of them in the Fly itfelf. Above the 
brain are fituated two white, foft, little parts, 
- fomewhat like knots, which rife like two horns: 
they are annexed to the fides of the thorax, 
and reft on the ftomach, as on a bafis or foun- 
dation. But what thefe little parts are, as alfo 
their ufe, Iam likewife hitherto ignorant. 
I afterwards likewife obferved in a Nymph, 
which I found dead in its fkin, that the purple 
fat was there variegated with white fpots. ‘The 
little inteftine, which I before defcribed to be 
contained within one of the inteftines, lay loofe 
therein, without adhering any where, and was 
curled; but that part of the inteftine, which 
enclofed it, feemed to be very confiderably di- 
lated. The uvea of the eyes was of a very 
beautiful bright purple. Here and there, in 
the abdomen, were feveral {mall Worms; 
fome of which were already changed into 
Nymphs, and appeared to me as if they were to 
56 
NAMIC U. RTs 
be transformed into Flies very foon. It would 
require a large treatife to deferibe how fuch 
things are produced in the bodies of other in- 
fects; and what f{trange and unheard-of things 
may be here further obferved. -So admirably 
does God fhew himfelf before our eyes.! and 
probably the relation would not be believed, if 
I defcribed and delineated that a Nymph iffues 
out of one fpecies of Caterpillars, which be- 
longs to the fecond mode of the third order ; 
and that out of this Nymph the Butterfly is 
afterwards produced; and that out of the fame 
{pecies comes .a Worm alfo, which is again 
changed into a Nymph, according to the firft 
mode of the third order, and at laft affumes 
the form of a Fly. And further, that out of 
the fame fpecies of Caterpillars, arife two or 
three Worms, which are again changed into 
Nymphs of the fourth order, and thefe after- 
wards into fo many Flies. 
eighty, nay one hundred Worms have iflued 
thereout, which have been likewifefirft changed 
into Nymphs, and afterwards into Flies. I 
have feen thefe twelve changes, which are very 
Of, 
worthy of notice, diftinétly in only one {pecies 
of Caterpillars. And now, at length, I have 
learned that all thefe- wonderful effects of Na- 
ture obtain likewife in water-infects; but this 
I have not yet fufficiently traced. 
Though the changes of the inteftines, a lit- 
tle before enumerated, are very fingular inthe 
Worm and Nymph of which I treat, thofe 
which the {pinal marrow undergoes deferves 
yet the greateft notice, and that preferably to 
the reft. For as this marrow in the Worn 
was twifted, as it were, into a curled lock; fo, 
on the other hand, we find it extended very 
ftraight in the Nymph, and almoft all its 
eleven knots, Tab. XE. ‘Fig: vir 1,- 2, +35 
&c. dragged or feparated from each other. 
This is chiefly feen about the laft knots; but 
not about the foremoft knots, or thofe next to 
the brain, @; near or on the upper part of 
which I have delineated the cornea of the eyes. 
The firft knot, 4, preferved its former fituation; 
but the four fubfequent knots, c, having fuf- 
fered a quite different change, were prefied 
clofer to each other than before, and expanded 
to a confiderable bump or fwelling; and 
therefore the nerves, fpringing from thence, 
were now conveyed in a very different manner. 
Nay, further, the crigination of the fpinal 
marrow is alfo feen, {tretched and extended 
between the firft and fecond knot: and this, 
indeed, may be perceived {till more plainly 
about the fixth, feventh, and eighth knot; 
and therefore only the three loweft knots, d, 
remain in their former fituation; though the 
laft of them is likewife more confpicuous than 
the two next above. If we would here follow 
Reafon as our guide, fhe would certainly have 
rather dictated, that the convolution of the 
marrow in the Nymph is extended in the 
* This double conftruction of the ovary is almoft univerfal in flying infeéts, and it is the fame in almoft all the kinds of fithes ; 
and the vaft number of eggs bears likewife an analogy. 
In many fifth the body of the female is filled with this ovary, as entirely 
as in gnfe@ts.. The intent of Nature feems to be the providing, from the abundant eggs and young of fome kinds, food for the 
others; for it never could be the intent, that all the eggs contained in thefe ovaries fhould yield perfect infects. 
Worm ; 
Laftly, that thirty, | 
