63 The BOOK 
wherefore, as the infect is and remains yet a 
Vermicle or Worm, and has fome of its parts 
enclofed in a skin and deprived of motion, like 
a Nymph of the third order or clafs, I have 
called it in this period a Nymph-Vermicle. 
Tn what manner this Nymph cafts its skin, is 
{hewn in the fecond figure, Tab. XII. fig. 11. 
VI. Laftly, I exhibit the fame Vermicle 
as it is when arrived to its laft degree of per- 
feGtion; in-which form it is -called-the Perla, 
Libella, or Dragon-Fly, and by increafing be- 
comes a perfect creature, becaufe it has ac- 
quired its full age and is now fit for generation. 
As at firft it was a creeping and {wimming 
Worm, it is now become a flying Worm or 
inhabitant of the air. Moreover, its change, 
or properly the accretion and expanfion of its 
parts, is, with refpect to its eyes, wings and 
tail, extremely admirable, but the legs undergo 
no change. 
I firft obferved thefe Worms, out of. which 
the Dragon-Flies are produced in the river 
Loire at Saumur, behind the houfe of the very 
learned Dr. Tanaguil Faber, whofe gueft I had 
then been, and who likewife greatly loved to 
fearch into fuch natural miracles. I afterwards 
found them in many other frefh rivers, {mall 
pools, fenny ditches, and other ftanding waters, 
and in fome places in fuch great numbers that 
the whole bottom was as it were planted with 
them. They can both creep and fwim, but 
they do not move {wiftly. They have like- 
wife a fharp fight, and they immediately throw 
themfelves to the bottom, if any one comes to 
the places wherein they live, or when they 
perceive the leaft uncommon object. Their 
food is foft mud, and a fine earthy fubftance ; 
wherein they live. They are produced by the 
Libelle or Dragon-Flies, for thefe are likewife 
ufually about waters, and in thofe places. per- 
form in a very wonderful manner the bufinefs 
of generation. Numerous Dragon-Flies are 
likewife found in the fields and forefts, where 
there are numerous {maller Flies; for, like birds 
of prey, they hunt after and devour the latter 
in the air. 
If the eggs which the Dragon-Flies throw 
into the water be examined with a microf- 
cope, they appear of an oblong figure, Tab. 
XI. fig. 1. and in the fore part terminate in 
a point: in this part they are alfo adorned 
with a kind of little cups, with protuberant 
points, fomewhat refembling the cups which 
we have delineated in the Nit or Loufe’s egg, 
and they are blackith in the extreme fore end. 
At the hinder part the egg terminates in an 
oval form, and has a glittering furface; befides 
this it has nothing fingular in it. : 
When the Worms which iffue out of thefe 
eges have grown to the form of a Nymph- 
Vermicle, they then remove out of the water 
to a dry place, as into the grafs, to pieces of 
wood, or a ftone wall, or any thing élfe they 
meet with; and therein firmly fixing the acute 
claws, Tab. XII. fig, 11. aa, of their legs, they 
continue immovable a very fhort time. It is 
a NAD UD RIES 
or, 
then obferved, that the skin firft opens in theit 
head and back; and out of this opening they 
exhibit to view their-real head and eyes 4, and 
at length their fix legs cc; whilf&t in the mean 
time the hollow and empty skin or flough of 
the legs remains firmly fixed in its place ; after 
this the enclofed creature creeps forward by 
degrees, and by this means draws firft its wings 
and then its body out of the skin, and proceed- 
ing a little further, fits at reft for fome time 
longer asif immovable. In this time its wings 
begin by degrees to expand themfelves, and to 
make {mooth and-even all their plaits and folds. 
The body is likewife infenfibly extended, until 
all the limbs have obtained their juft fize and 
bignefs. As all thefe things are perfected by 
the force of ‘blood and circulating humours, 
and by the affiftance of the air impelled by ref- 
piration, the creature cannot the firft moment 
fly, and therefore is forced to ftay in the fame 
place, until all ats limbs are dried by the circum- 
ambient air and fun. Thus the Dragon-Fly 
enters upon a more noble life than that it had 
hitherto led in the water, for in the latter it 
was obliged to live in mifery, creeping and 
fwimming flowly, but now it wings the air. 
Itis very feldom that thefe changes of infects 
are prefented to view by nature, and it hap- 
pened by mere chance that I obferved them 
for the firft. time : one of thefe Vermicles ad- 
hered to a ftone wall in the river Loire, and it 
was fo foftened by the waves dafhing againit it, 
that it could only half perfect its change, fo 
that I took it partly free, and partly yet fixed 
in the skin. I once afterwards faw this change 
in the large kind of Dragon-Fly, which had 
crept to land out of a {mall lake, and caft its 
skin fitting in the grafs. In the fmalleft Dra- 
gon-Flies, which are very numerous in Holland, 
and of which Goedaert has deferibed the muta- 
tion, it is not fo difficult ta difcover this mat- 
ter, as T have long ago fhewn it to many, and 
amoneft the reft to Dr. Matthew Slade. 
Another thing worthy of obfervation in thefe 
creatures is, that they muift hunt and feek after 
their food flying in the air, for which purpofe 
nature has given them two large eyes, which 
make almoft the whole head, and are like glit- 
tering mother-of-pearl. They have moreover 
four remarkable membranous filver-coloured 
wings, with which, as with oars, they can turn 
themfelves like fwallows with a prodigious 
velocity to all parts of the air. But to this 
the very long tail that they have is alfo condu- 
cive, for with this they fteer and govern them- 
felves with great art, and prepare themfelves a 
certain path through the air. Mouffet, who 
erroneoufly afferted, that thefe creatures were 
produced from rotten bull-ruthes, {peaks how- 
ever very rationally of them, when he fays: 
‘© They form one of the greateft beauties in all 
«* nature, being fuperior by far to all art.” 
The eyes of the Dragon-Fly are of a reticu- 
lar ftruéture, and are divided by a double 
feries of interfeétions, as I have defcribed in 
another place. Within the mouth are to be 
feen 
