tiT4 
tations into the water. ‘This ufually happens 
in the evening between fix of the clock and 
half an hour after. This I obferved onthe 
thirteenth of the month of June, in the year 
1671, purfuing the change of the Worms of 
the Ephemerus. 
The other Worms, which are not as yet 
come to this ftate of growth, remain in their 
cells. 3 
ter move forward, and make all the hafte they 
can from the bottom to the furface ; which, 
when fome more fwiftly and others more 
flowly are arrived at, each of them, fig. vir. 
is changed into a winged infect, fig. v1. and 
vill, But this change or cafting of the fkin 
is fo fuddenly performed, that even the moft 
attentive perfon cannot otherwife judge, than 
that the Worm breaks or burfts its way and 
{wiftly flies out of the middle of the water. 
Every infect that I have hitherto obferved 
has a certain and determined time appointed 
for it by the omnipotent God, to expand its 
wings and dry them, that they may become 
{mooth and polifhed, before they are able to 
prepare themfelves for flight. But the Ephe- 
merus, on the contrary, is almoft at one and the 
fame point of time a reptile and a flying crea- 
ture. Wherever one fees at this time a little 
water bubble up, if we cafts our eyes on the 
furface, there is immediately a winged infect 
obferved to iffue out of the middle of the 
water. Argus would want eyes, if he fhould 
attempt to trace thefe miracles of the adorable 
Creator of the univerfe. , 
If any one goes into a boat and fixes in a 
fituation directly againft the defcending ftream 
of a river, then he may very well fee thefe 
infects emerging or rifing up, and cafting their 
skin. For, though you fhould as foon as pofli- 
ble catch the Worm {till floating on the water, 
yet you can fcarce look at it before it is winged 
and flying. ‘This may however be prevented, 
and the Worm taken out of the river before 
the change is performed, if it be ftruck a little, 
or bruifed on the breaft ; which is neceflary to 
be. done, if one would view the creature at 
this period not yet changed, but covered with 
its skin. 
It is difficult to fay what is the reafon that 
thefe wings are fo {wiftly expanded, and yet 
have neither mufcles nor joints in them, but 
only artificially plaited and folded; nay, they 
muft again change their skin the moment 
after, his difficulty furely is very worthy to 
be folved. I indeed thought it neceffary that 
thefe wings fhould be provided with mutcles 
and joints in the fubftance of them, as we 
have obferved in many other infects; for the 
latter can by the help of fuch joints and muf- 
cles very artificially contract their wings into a 
narrow compafs, and again quickly unfold or 
difplay them. This holds, amongft the reft, 
in Ear-wigs, which hide or put up very long 
wings in a fmall fheath, which folds and co- 
vers them fo neatly, that they feem to be quite 
deftitute of wings. But though the Ear-wigs 
Thofe which have crept into the wa- » 
The BOOK of NATURE; or, 
can by the power of mufcles and joints, which 
they have in the middle of their wings, clofe- 
ly fold thefe wings in the {fame manner as in 
the Ephemerus, which has not yet gone through 
its change, and again quickly expand them; 
and though I thought the Ephemerus was in 
need of the like affiftance, yet the fupreme 
Architect has not been pleafed to make ufe of 
the fame ftructure; and it appears that even 
this ftru€ture was not neceflary. 
If the trials that I have hitherto made can ° 
throw any light on this inftantaneous expanfion 
of the wings, it muft confift in this; that I 
think the water, which is warmer on the fur- 
face than in the bottom of the river, flowing 
all over and penetrating into the wings, con- 
tributes very much to their expanfion. For by 
the affiftance of the water, the blood which 1s 
then driven out of the heart into the wings, 
in order to promote this needful expanfion, 
may be impelled with greater force, in the 
fame manner as we fee the blood is, by the 
help of hot water, drawn more plentifully into 
the feet, and thofe parts are more diftended 
when any one is blooded in the foot. Thus, 
becaufe the blood and all the humours in this 
infect, when it gets into the water {wims 
about and is employed in changing its skin, 
are violently moved; hence the furrounding 
water may be of great fervice to impel the hu- 
mours contained in the wings, fo that they 
may. be more expanded. Wherefore we like- 
wife obferve that in the wings of infects, if 
wounded at that time, there follows a mortal 
hemorthage, or if the creature farvives, the 
wings are never afterwards difplayed. ‘To the 
more ready expanfion of thefe wings, the im- 
pelled air likewife probably contributes very 
much, becaufe it is conveyed thither through 
the numerous pulmonary tubes, and may ferve 
for giving ftrength and firmnefs to the pulmo- 
nary pipes, and for expelling the humour 
from thence. If you cut off the wings of the 
Worm of the Ephemerus when it is very near 
its change, and throw them into a bafon of 
water, you will immediately fee them expand- 
ing by force of the water flowing round them, 
and at length extending themfelves into their 
natural, {mooth, and even furface, fo that they 
would ferve the creature to fly, if they were 
dry and ftrong enough. I have often made 
this experiment on the wings of this infect, 
and by that means have in fome meafure learned 
how they are expanded. When I have put 
them in the water, in the manner beforemen-. 
tioned, I have obferved that their larger folds 
were firft opened, Tab. XIV. fig. 1. ¢¢¢, and 
then, by degrees, the wings were ftretched out 
in length, Tab. XIII. fig. rx. Afterwards the 
longitudinal plaits of the wings were expand~ 
ed, fig. x. until at length the whole wings, 
fig, x1. were entirely fhewn open, ‘This may 
be feen in the infeét itfelf, fig. vitz. which I 
have delineated from the life; but the figures of 
the wings beforementioned are drawn with 
the help of a microfcope. So long as the wings 
con- 
