The 
Gare He aay 
Eels POP wy 
a FNS 2 GW S. 
ie. VIL. : 
The figns by which to difcover, whether the Ephemerus is to fly in a fhort time ; 
as alfo what may prevent it, and to what clafs or order of natural changes 
it belongs. 
pe HE general preceding figns of the ap- 
proaching change of the Worms of the 
Ephemeri into flies, are, in regard to the wea- 
ther, a warm and dry fpring; a mild winter, 
without much rain or fnow; and a gently 
running water. The peculiar figns whereby 
to know that thefe Worms will change into 
Flies in a fhort time, confifts in a protuberance 
of the wings on the back; for about that time 
the {mooth and -deprefled form of the upper 
part of the body is changed into a more {wollen 
and rounder fhape; that is, that glutinous 
fluid which is at other times found in the coats 
that furround and defend the wings, becomes 
thicker and more clammy: hence it is, that 
the wings are at that time in fome degree vifi- 
ble through their external skin, Tab. XIII. 
fig. vil. aa. 
Thefe figns are more certain when the co- 
lour of the wings within is obferved to change 
from a yellowifh and palifh to a grayifh hue. 
There is alfo a ftill greater certainty, if, after 
the external coat of the wings is taken off from 
the infect’s body, the wings can be expanded 
without hurting them: as appears in Tab. 
XIV. fig. 1. under the letters see; where I 
exhibit the magnified wing, and as it is art- 
fully folded by nature. 
Another fign likewife prefents itfelf in the 
diffection of thefe infects: that is, when we 
find the genital parts and eggs have acquired 
their full bignefs, their due hardnefs, and true 
figure. We may then take the whole creature 
out of its skin, by art, and by this contrivance 
change it into the form of a flying Ephemerus 
- ourfelves, not waiting the moment of nature, 
All the vifcera of this infe@: are then cleared 
from their contents, which were a kind of 
dirt; nor is there any thing in the ftomach 
and inteftines but tranfparent and depurated 
humours, which appear the more dusky, foul, 
and coloured; the further the time of the 
change is diftant; fo that they are fometimes 
C reeks A 
yellowifh, and fometimes dusky and red. At 
other times a little mud is found in the extre- 
mity of the thick and ftraight gut and colon ; 
but, onthe contrary, thefe infects are all over 
clear and tranfparent, when the time of their 
change is juft at hand. 
The following accidents keep back the 
changes of the Ephemerus, deftroy its life, or 
prevent its growth; infomuch that fo great 
numbers of thefe infects are not produced as 
might be expected ; nor do they come to fuch 
maturity. An inclement, boifterous, tem- 
peftuous, long, rainy and fnowy winter, de- 
ftroys numbers. By this the cells inhabited by 
the Worms ate deftroyed, being worn out, or 
fhut up and covered with fand. ‘Too much 
drought or dry weather afterwards occafions 
the fame deftruction ; for they are then com- 
pelled to quit their little cells, and make them- 
felves new ones from the decreafe of the wa- 
ter; and many are loft in this operation. 
From what has been faid, we may eafily fee 
what favours and what injures the Ephemerus ; 
what leffens it troubles and misfortunes, and 
what increafes and multiplies them. 
What I have a little before advanced con- 
cerning the maturity of the wings, fhews to 
which of the orders of the four natural tranf- 
mutations this infect belongs; that is, to the 
fecond clafs or order. For all the infe&s of 
this order are changed in the fame manner as 
the Ephemerus. : 
Indeed, Clutius feigns that the Worm of the 
Ephemerus is changed into a Nymph of the 
third order, and on this lofes all its motion, 
- like the Nymphs of Silk-worms ; he even ex- 
hibits a figure of that Nymph, though there 
is no fuch thing in allnature. Hence it is evi- 
dent how much they are deceived who negle& 
the truth of experiments, and give credit to 
their own reafonings, or to the falfe relations 
of others. 
JF VUr. 
How and in what a wonderful manner the Worm is transformed into an 
Ephemerus. 
HEN the time of the change of the 
Worm of the Ephemerus is approach- 
ing, and the wings, Tab XTII. fig. VII. aa, 
hidden in the cafes or hufks, have acquired 
their due ftreneth and form, and that it is no 
longer in the power of the Worm to delay its 
change; thdfe which have their parts thus dif- 
pofed and prepared, march out of their habi- 
G ¢ 
g tations 
