the oH So TOL RAY Sor aun’ sf GT's, 
continue in their plaits and folds, they are of 
adark gray colour; but this by degrees becomes 
more faint when they are expanded. 
When the Ephemerus has, fig. vi. and vrut. 
taken its firft flight, it feeks out with all {peed 
for fome place where it may quietly reft ; and 
having found fuch a one, it cafts off, fig. 
xii, and x11. a very thin and tender skin 
from its whole body, that is, from its head, 
breaft, belly and wings. But before I treat of 
this other change of the skin, I muft ob- 
ferve that it is always made on dry land, 
whereas the former is conftantly performed in 
the water. And the firft change is likewife 
much more admirable and worthy of obferva- 
tion than the fecond. When the Ephemerus 
firft caft its skin or outward coat on the furface 
of the water, it at that time entirely lofes its 
former fhape; but this is not the cafe in the 
fecond change. 
Therefore under the firft of thefe changes, 
in which the skin of the Worm opening on 
the head and back, fuddenly is feparated from 
the body, until the Fly {peedily and quickly 
makes its way from thence, fome very 
confiderable parts are loft, that is, fig. rv. 
Ff; all the branchie or gills on each fide, 
together with the ten rowing fins under them. 
Nay, when thefe branchiz are feparated, they 
do not leave even their hairs upon the body, 
but all vanith away fo entirely, that only fome 
{mall veftiges or points remain of them, which 
form a little margin or border on the fides of 
the belly. The Ephemerus lofes alfo its teeth 
or forceps c, and the former fhape dd of its 
legs, and the cafes of its wings e, and tails g, 
and other parts. Hence the Ephemerus having 
gone through this change of its skin, is become 
as it were another creature. fig. vi. and vi1t. 
But as it is very difficult, perhaps impof- 
fible to obferve all thefe things in the very fhort 
{pace of time in which the skin is cafting, any 
perfon may do this at his leifure, if he gently 
and dextroufly ftrips the Worm, that is to 
change immediately, of its skin. For then the 
parting branchiz or gills, which adhere to the 
exuvie or caftskin of the Worm, are feen very 
plainly: there likewife appear thofe prominent 
apiculi or points they leave on the body of the 
Ephemerus itfelf; nay, you may likewife fee 
thofe little holes which received the apiculi or 
points juft mentioned. The pulmonary tubes 
may be likewife feen. Why fhould I fay any 
thing of the mufcles, tendons, veffels, and 
nerves which are feparated from their mem- 
branes, like ripe fruit falling from a tree? for 
neither reafon, obfervation, nor experience can 
difcover any thing of them, fince they are all 
directed by the omnipotent wifdom and provi- 
dence, and conducted in fuch a wonderful 
manner that they are altogether incomprehen- 
fible. 
Again, though many parts of the Worm of 
the Ephemerus are extended and become longer 
under the firft change of its skin, yet the 
horns which projet from the fore part of the 
Lig 
Worm’s head only caft their skin, and when it 
isoff they become more flender and fhort in the 
flying Ephemerus than they were in the Worm 
itfelf. “The change that happens about the eyes 
merits yet greater attention, for their cornea 
tunica which was of a {mooth and equal furface 
in the Worm, feemsin the Ephemerus, after 
cafting its skin, to confift of a congeries of 
many eyes, which form a little net equally di- 
vided. The legs likewife, together with two 
of the tails, become as long again by the 
change : but the third or middle tail is entirely 
taken off, having ferved no purpofe but to the 
Worm. 
When I fay the two eyes of this creature are 
compofed of a congeries of leffer eyes, fix, nay 
feven thoufand of which I have obferved thus 
cluftered together in fome infects, whereas in 
others, as Spiders and Scorpions, they are dif- 
perfed all over the body; I would not have any 
one conclude from thence, that thefe eyes are 
formed as they are in the human fpecies and 
other known animals. They are by no means 
fuch, for they want the humours; but every 
globular divifion of them emits an hexago- 
nal filament like a needle, which terminates in 
the net-like tunic or coat of the eyes, and this 
coat itfelf ends at the nerve and brain: fo 
that thefe creatures fee in a different manner 
fromus. We fee by the affiftance of rays col- 
lected on the infide of our eyes, but thefe per- 
form vifion by a colleGtion of nervous fila~ 
ments, which, when they fee, are lightly and 
gently affected and moved in their prominent 
extremities by vifible obje@ts, and by the rays 
of light or colours and other appearances, as I 
have defcribed at large, and exprefled in figures 
in my treatife on Bees. 
As to the fucceeding change of the skin of 
the Ephemerus, which immediately and without 
interruption follows the firft, we are to ob-. 
ferve therein, that the Ephemerus having once 
caft its skin, choofes no particular place to reft 
or fettle in, in order to undergo the other. 
It fixes upon any place it can find in its fight, 
and it does not regard whether it be wood, 
ftone, earth, a tree, a boat, a {hip, a beaft, or 
aman. It feems to be a moft innocent little 
creature indifferent to every thing, fo that it 
can re{t any where, in order to caft off this 
fecond skin, which is done in the manner fol- 
lowing. 
The Fly firmly and ftrongly faftens its legs, 
which are armed with fharp claws for that 
purpofe; then it appears as if feized with a 
fhuddering and trembling motion, and imme- 
diately its skin opens on the middle of its back 
in the {mall fhield that is placed there: this 
opening becomes by degrees fo large towards 
the fore parts, that the creature can thrut its 
head out of it. After this it draws its legs alfo 
out of the skin, Tab. XIII. fig. x11, xrir. 
whilftthe claws, adhering to the caft skin, are 
in the mean time ftill firmly fixed in their 
places; and this indeed contributes much to re- 
move the skin from the reft of the body. 
Moreover, 
