Thea Hl eS: Oo Re YO oe JU NSS FE Coa Ss 
a9. 
The natural changes of the firft clafs or order of infe&ls, exemplified in the Loufe ; 
with an explanation of what relates in general to the other three claffes. 
a HAT I may give a fingulat and fatis- 
factory {pecimen of the firft clafs of in- 
fects, I fhall here inferta letter, formerly wrote 
with great care to Mr. Thevenot, as it con- 
tains a complete and exact account of the limbs 
and parts of a Loufe, both internal and exter- 
nal. This example, by which I propofe to 
illuftrate the firft clafs of infe&ts, and the ex- 
amples I fhall give, in their due places, for the 
other three claffes, will enable the reader to 
form a competent judgment of the changes, 
which all other infects undergo, according to 
the different clafles to which they belong. It 
muft be allowed, however, that whatfoever 
pains we may take to arrange them, there will 
ftill remain, even amongft thofe of the fame 
clafs, very remarkable differences; and fome 
of thofe differences will be in the mutations 
they undergo. ‘This will moft clearly appear 
from our experiments relating to the fourth 
clafs, in the cafe of the worm-like Nymph of 
of the Afilus Fly, and in the egg-like Nymph 
of the common Fly; between which there is 
no fimall difference, though they belong to the 
fame clafs, and are liable afterwards to the 
famechanges, ‘This accidental difference may 
alfo be feen on looking over the figures of ani- 
malcules, which I have given under each kind 
in the fpecial hiftories of the three other claffes. 
It appears very ftrikingly in the Cryfallides of 
Caterpillars, as they are exhibited in the de- 
figns of the indefatigable Goedaert; for though 
they all belong to the fecond mode of our third 
elafs, yet one Chryfalis differs in many parti- 
culars from another: this difference is, how- 
ever, far from being what is called effential, 
it only confifts in fome part of the external 
forms. 
From the firft clafs of our changes, we fhall 
now felect the Loufe as an example, and re- 
prefent by figures, the changes which happen 
In its parts, till it comes to its full growth. 
The Libella, or Dragon Fly, will ferve us for 
the fecond clafs; and the Ant for the firt 
mode of the third; the nocturnal Butterfly for 
the fecond. Laftly, we fhall give the com- 
mon Fly as a {pecimen of the fourth clafs; 
and I {hall afterwards illuftrate thefe feveral 
changes by the accretion of the limbs in a 
Frog, and the budding out, or fhooting, of 
the parts of a flower. 
Though the foregoing natural changes, and 
the comparifons of others which will be made 
in treating of them, may be thought fufti- 
cient for giving a clear idea of the practices of 
the infects contained under the four claffes, 
into which I have arranged them, and of the 
differences between each clafs; neverthelefs, 
I fhall add to the firft clafs, a feparate and {a- 
tisfactory account of the manner wherein the 
parts of Snails grow and are changed, I thall 
do the fame by the Ephemeron, or Fly of 
one day, in the fecond clafs. In the third 
clafs I fhall exhibit, according to the firft 
mode, all the changes of the Bee, with a com- 
plete diffection of that infect and the horned 
Beetle ; and the fame both in defcriptions and 
by. figures of the common day Butterfly, ac- 
cording to the fecond mode of the third clafs. 
Laftly, I thall give in the fourth clafs an ac- 
count of all the changes which the Afilus, or 
Gad Fly is fubje& to, and illuftrate them with 
plates, I fhall, befides thefe, infert various 
other hiftories, all which will not only throw 
a light upon each other, and reprefent clearly 
and diftintly the changes of the four claffes in 
the exact manner wherein they happen, but, 
what is much more advantageous in this kind 
of ftudy, they will difplay fuch miracles of 
wifdom, power, and goodnefs in the great 
Creator, as cannot fail powerfully to incite us 
to love and adore him. ‘This, indeed, is the 
great purpofe I propofe to myfelf in my inqui- 
ries concerning thefe natural mutations. 
To fet forth clearly and diftin€tly the orders 
of the tranfmutations in the Loufe and Dragon 
Fly, the nocturnal Butterfly, and common F'ly, 
and to exhibit more plainly the changes of each 
of them ; asalfo that I may be able to demon- 
ftrate thofe, wherein the orders of the changes 
agree or difagree among themfelves: I fhall 
ufe the fathe number, and obferve the famé 
rule in explaining the five refpective figures. 
For though there be not the fame ‘ecefity to 
proceed in the fame manner in fetting forth all 
the figures of the changes and accretions ob- 
ferveable in thofe infects; as for éxample in 
the change of the Loufe, which is only a fim- 
ple augmentation ; yet, fince we fee five dif- 
tinct changes in the Libella, or Dragon Fly, 
and other infects, whofe figures we exhibit 
before they attain their fullage, and are ren- 
dered fit for generation, we have been, as it 
were, obliged to treat the Loufe in the fame 
regular manner, in order to render the whole 
more exact and uniform, as we have before 
done in comparing the Frog with the flower 
or vegetable incteafe. 
We have not obferved that method alfo in 
the particular hiftories of Bees and the reft, as 
well becaufe their anatomy are fubjoined to 
thofe accounts, as that the claffes we have ad- 
vanced, feemed calculated to exhibit a certain 
general rule, whereby all the changes of infects 
produced by nature may be tried and ex- 
amined. 
Finally, every thing marked in numbers 
in the explanations of the figures, is delineated 
in its natural bignefs; but the Animalcules, to 
whofe figures the numbers 1, 2, Ry cde, ate 
affixed, are reprefented as they are magnified 
by the microfcope; while fome others that are 
i charace 
