The Eggs of Silk-worms (one of which I have describ’d in the second
_Figure_ of 25. _Scheme_) afford a pretty Object for a _Microscope_ that
magnifies very much, especially if it be bright weather, and the light of a
window be cast or collected on it by a deep _Convex glass_, or Water-ball.
For then the whole surface of the Shell may be perceiv’d all cover’d over
with exceeding small pits or cavities with interposed edges, almost in the
manner of the surface of a Poppy-seed, but that these holes are not an
hundredth part scarce of their bigness; the Shell, when the young ones were
hatch’d (which I found an easie thing to do, if the Eggs were kept in a
warm place) appear’d no thicker in proportion to its bulk, then that of an
Hen’s or Goos’s Egg is to its bulk, and all the Shell appear’d very white
(which seem’d to proceed from its transparency) whence all those pittings
did almost vanish, so that they could not, without much difficulty, be
discern’d, the inside of the Shell seem’d to be lin’d also with a kind of
thin film, not unlike (keeping the proportion to its Shell) that with which
the shell of an Hen-egg is lin’d; and the shell it self seem’d like common
Egg-shells; very brittle, and crack’d. In divers other of these Eggs I
could plainly enough, through the shell, perceive the small Insect lie
coyled round the edges of the shell. The shape of the Egg it self, the
Figure pretty well represents (though by default of the Graver it does not
appear so rounded, and lying above the Paper, as it were, as it ought to
do) that is, it was for the most part pretty oval end-ways, somewhat like
an Egg, but the other way it was a little flatted on two opposite sides.
Divers of these Eggs, as is common to most others, I found to be barren, or
addle, for they never afforded any young ones. And those I usually found
much whiter then the other that were prolifick. The Eggs of other kinds of
Oviparous Insects I have found to be perfectly round every way, like so
many Globules, of this sort I have observ’d some sorts of Spiders Eggs; and
chancing the last Summer to inclose a very large and curiously painted
Butterfly in a Box, intending to examine its gaudery with my _Microscope_,
I found within a day or two after I inclos’d her, almost all the inner
surface of the Box cover’d over with an infinite of exactly round Eggs,
which were stuck very fast to the sides of it, and in so exactly regular
and close an order, that made me call to mind my _Hypothesis_, which I had
formerly thought on for the making out of all the regular Figures of Salt,
which I have elsewhere hinted; for here I found all of them rang’d into a
most exact _triagonal_ order, much after the manner as the _Hemispheres_
are place on the eye of a Fly; all which Eggs I found after a little time
to be hatch’d, and out of them to come a multitude of small Worms, very
much resembling young Silk-worms, leaving all their thin hollow shells
behind them, sticking on the Box in their _triagonal_ posture; these I
found with the _Microscope_ to have much such a substance as the Silk-worms
Eggs, but could not perceive them pitted. And indeed, there is as great a
variety in the shape of the Eggs of Oviparous Insects as among those of
Birds.
Of these Eggs, a large and lusty Fly will at one time lay neer four or five
hundred, so that the increase of these kind of Insects must needs be very
prodigious, were they not prey’d on by multitudes of Birds, and destroy’d
by Frosts and Rains; and hence ’tis those hotter Climates between the
_Tropicks_ are infested with such multitudes of Locusts, and such other
Vermine.
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