Th HISTORY of INSECTS. 
defcribing; but I have obferved that others of 
them live longer than thefe. I therefore ap- 
prehend that the various fpecies are diftin- 
guifhable from each other by feveral further 
peculiarities; and, for this reafon, I do not 
pronounce thofe authors reproachable, who 
relate any thing of thefe or of the like infects, 
becaufe what they fay does not exactly agree 
with the fpecies of one particular country. 
Far be it from me to be guilty of fuch terme- 
rity ; fince God is infinite in all his works, 
and the {pecies may be numerous. 
About the end of June 1670, when I re 
fided in the village of Slooten near Amfterdam, 
I went fometimes in the evenings into the 
fields, where fo great a number of minute in- 
fects which were fomewhat larger than Gnats, 
at times pitched on my cloaths, that I was all 
over covered with them. Each of thefe caft 
-a {mall {kin on my cloaths ; after which, I ob- 
ferved that all of them returned to the water, 
and there, like the larger Ephemerus, {ported 
and beat up anddown. ‘Thefe infects are pro- 
duced nearly in the fame manner as the Ephe- 
merus before defcribed ; for they live in ditches 
and water-trenches, and when they are to fuf- 
fer a change into the Fly ftate, they likewife, 
at regular times, caft two skins, one in the 
water and another on the land. The Worms 
of the fmaller Ephemerus differ from the lar- 
11g 
ger, in that they do not hide themfelves in 
mud, or form cells or long holes, but moftly 
inhabit ftony and fandy bottoms: therefore 
nature has formed them of a rougher and 
more robuit conftitution than the larger Ephe- 
merus. Their skin alfois more like the crufta= 
ceous integument of Crabs and Shrimps, They 
have likewife branchize or gills, and rowing * 
fins on the fides of their bodies. When in 
the middle of fummer any one takes up {tones 
from the Rhine or Leck, or other colleétions 
of waters in our own country, for carrying to 
the land, he will moft commonly fee fome 
Worms of that kind fticking to them; which 
is likewife the cafe in other countries and other 
rivers, as I myfelf have learned from expe- 
rience in the Loire, the Seine, and other 
rivers of France. Hence it is evident that 
there are many diftin& fpecies of the Ephe- 
merus, and that the authors who defcribe an 
Ephemerus, however different from that of our 
country, do not merit certain cenfure. I can 
for the moft part exhibit to the naked eye the 
Worms before mentioned, and every" thing 
that I have hitherto advanced concerning the 
Ephemerus, according as they are in nature ; 
fince I have preferved them to this day, that 
they may ferve the better to illuftrate and con- 
firm what is faid in this treatife. 
The end of the wonderful hiftory of the EpuEMERUS: 
The 
i Ti Pee D 
Cy RIMS Ep aera 
Of natural changes, or flow accretions of the parts of infeéds. 
HY NG explained in the preceding 
chapters the two firft orders or claffes of 
natural changes, we now advance to the third ; 
which, we muft obferve, is always preceded 
by another change, as we have before defcrib- 
ed at large. 
As this change is more obfcure and intricate 
than the firft, and more difficult to be under- 
ftood than the fecond, in order to give a dif- 
tin and plain defcription thereof, we thall 
compare it with the firft and fecond ; for by 
this means it will be eafier to comprehend 
what they all three have in common, and in 
what they differ from each other. As the 
firft order of tranfmutations.confift in this, that 
the creature increafes in its parent from almoft 
invifible, but really exifting rudiments, and 
lies enclofed ina membrane until it has ac- 
quired fufficient ftrength therein to be able to 
creep out of it; fo on the other hand, the 
other order is much more imperfect ; for in 
this the infect increafes likewife as in the firft 
order, but it comes out of its egg imperfect ; 
and therefore becaufe in fome parts, but chiefly 
in regard to the wings, it is ftill defective; it 
muft, in order to acquire its due perfection, 
take in food from abroad ; by the help of 
which, the reft of its parts, which we from 
time to time obferve to increafe and expand, 
like a flower from its cup, are at length per- 
fected. 
The ordet of nature is quite contrary in 
thofe infects which undergo the change of our 
third order: for though they increafe in the 
fame manner as thofe in the firft order, and 
come forth imperfeét, as thofe in the fecond 
order, nay, much more fo, out of their ege, 
many of them not having even legs; yet all 
thefe imperfect parts are increafed and aug- 
mented in a very obfcure manner under the 
skin. Hence, as the creature iffues complete 
in all its parts out of the ege in the firtt order, 
and in the fecond the accretion or expanding 
of its feveral parts is performed externally and 
openly ; but in this our third order, on the 
contraty, this germination or fprouting is all 
tranfacted within the covering of a skin, and 
can with very great difficulty be obferved, un- 
lefs by the change of the skin. 
As therefore thofe infects which undergo 
the firt order of tranfmutation, conftituted 
under the form of a Nymph, creep only fim- 
ply out of their ege or fkin: and as thofe 
which belong to the fecond order of changes, 
likewife 
