With all grubs and all animals that break out from the grub
state, generation is due primarily to the heat of the sun or to wind.

Ascarids are more likely to be found, and grow with unusual
rapidity, in places where there is a deposit of a mixed and
heterogeneous kind, as in kitchens and in ploughed fields, for the
contents of such places are disposed to rapid putrefaction. In autumn,
also, owing to the drying up of moisture, they grow in unusual
numbers.

Gnats grow from ascarids; and ascarids are engendered in the
slime of wells, or in places where there is a deposit left by the
draining off of water. This slime decays, and first turns white,
then black, and finally blood-red; and at this stage there originate
in it, as it were, little tiny bits of red weed, which at first
wriggle about all clinging together, and finally break loose and
swim in the water, and are hereupon known as ascarids. After a few
days they stand straight up on the water motionless and hard, and by
and by the husk breaks off and the gnats are seen sitting upon it,
until the sun's heat or a puff of wind sets them in motion, when
they fly away.

From the cabbage is engendered the cabbageworm, and from the
leek the prasocuris or leekbane; this creature is also winged. From
the flat animalcule that skims over the surface of rivers comes the
oestrus or gadfly; and this accounts for the fact that gadflies most
abound in the neighbourhood of waters on whose surface these
animalcules are observed. From a certain small, black and hairy
caterpillar comes first a wingless glow-worm; and this creature
again suffers a metamorphosis, and transforms into a winged insect
named the bostrychus (or hair-curl).

From one particular large grub, which has as it were horns, and in
other respects differs from grubs in general, there comes, by a
metamorphosis of the grub, first a caterpillar, then the cocoon,
then the necydalus; and the creature passes through all these
transformations within six months. A class of women unwind and reel
off the cocoons of these creatures, and afterwards weave a fabric with
the threads thus unwound; a Coan woman of the name of Pamphila,
daughter of Plateus, being credited with the first invention of the
fabric. After the same fashion the carabus or stag-beetle comes from
grubs that live in dry wood: at first the grub is motionless, but
after a while the shell bursts and the stag-beetle issues forth.

The same remarks are applicable to all such insects as are
developed out of the grub, both such grubs as are derived from the
copulation of living animals and such as are generated without
copulation on the part of parents. For the grub of the bee, the
anthrena, and the wasp, whilst it is young, takes food and voids
excrement; but when it has passed from the grub shape to its defined
form and become what is termed a 'nympha', it ceases to take food
and to void excrement, and remains tightly wrapped up and motionless
until it has reached its full size, when it breaks the formation
with which the cell is closed, and issues forth. The insects named the
hypera and the penia are derived from similar caterpillars, which move
in an undulatory way, progressing with one part and then pulling up
the hinder parts by a bend of the body. The developed insect in each
case takes its peculiar colour from the parent caterpillar.

The so-called psyche or butterfly is generated from caterpillars
which grow on green leaves, chiefly leaves of the raphanus, which some
call crambe or cabbage. At first it is less than a grain of millet; it
then grows into a small grub; and in three days it is a tiny
caterpillar. After this it grows on and on, and becomes quiescent
and changes its shape, and is now called a chrysalis. The outer
shell is hard, and the chrysalis moves if you touch it. It attaches
itself by cobweb-like filaments, and is unfurnished with mouth or
any other apparent organ. After a little while the outer covering
bursts asunder, and out flies the winged creature that we call the
psyche or butterfly. At first, when it is a caterpillar, it feeds
and ejects excrement; but when it turns into the chrysalis it
neither feeds nor ejects excrement.

With regard

to insects, that the male is less than the female
and that he mounts upon her back, and how he performs the act of
copulation and the circumstance that he gives over reluctantly, all
this has already been set forth, most cases of insect copulation
this process is speedily followed up by parturition.

All insects engender grubs, with the exception of a species of
butterfly; and the female of this species lays a hard egg,
resembling the seed of the cnecus, with a juice inside it. But from
the grub, the young animal does not grow out of a mere portion of
it, as a young animal grows from a portion only of an egg, but the
grub entire grows and the animal becomes differentiated out of it.

And of insects some are derived from insect congeners, as the
venom-spider and the common-spider from the venom-spider and the
common-spider, and so with the attelabus or locust, the acris or
grasshopper, and the tettix or cicada. Other insects are not derived
from living parentage, but are generated spontaneously: some out of
dew falling on leaves, ordinarily in spring-time, but not seldom in
winter when there has been a stretch of fair weather and southerly
winds; others grow in decaying mud or dung; others in timber, green or
dry; some in the hair of animals; some in the flesh of animals; some
in excrements: and some from excrement after it has been voided, and
some from excrement yet within the living animal, like the
helminthes or intestinal worms. And of these intestinal worms there
are three species: one named the flat-worm, another the round worm,
and the third the ascarid. These intestinal worms do not in any case
propagate their kind. The flat-worm, however, in an exceptional way,
clings fast to the gut, and lays a thing like a melon-seed, by
observing which indication the physician concludes that his patient is
troubled with the worm.

From one single egg comes one single sepia; and this is likewise
true of the young calamary.

The male calamary differs from the female; for if its
gill-region be dilated and examined there are found two red formations
resembling breasts, with which the male is unprovided. In the sepia,
apart from this distinction in the sexes, the male, as has been
stated, is more mottled than the female.

The sepia

lays her spawn near to land in the neighbourhood of
sea-weed or reeds or any off-sweepings such as brushwood, twigs, or
stones; and fishermen place heaps of faggots here and there on
purpose, and on to such heaps the female deposits a long continuous
roe in shape like a vine tendril. It lays or spirts out the spawn with
an effort, as though there were difficulty in the process. The
female calamary spawns at sea; and it emits the spawn, as does the
sepia, in the mass.

The calamary and the cuttle-fish are short-lived, as, with few
exceptions, they never see the year out; and the same statement is
applicable to the octopus.

The female sepia goes pregnant in the spring-time, and lays
its eggs after fifteen days of gestation; after the eggs are laid
there comes in another fifteen days something like a bunch of
grapes, and at the bursting of these the young sepiae issue forth. But
if, when the young ones are fully formed, you sever the outer covering
a moment too soon, the young creatures eject excrement, and their
colour changes from white to red in their alarm.

Crustaceans, then, hatch their eggs by brooding over them as
they carry them about beneath their bodies; but the octopus, the
sepia, and the like hatch their eggs without stirring from the spot
where they may have laid them, and this statement is particularly
applicable to the sepia; in fact, the nest of the female sepia is
often seen exposed to view close in to shore. The female octopus at
times sits brooding over her eggs, and at other times squats in
front of her hole, stretching out her tentacles on guard.

When it has come into being the young sepia is first
distinctly formed inside out of the white substance, and when the
egg bursts it comes out. The inner part is formed as soon as the
female lays the egg, something like a hail-stone; and out of this
substance the young sepia grows by a head-attachment, just as young
birds grow by a belly-attachment. What is the exact nature of the
navel-attachment has not yet been observed, except that as the young
sepia grows the white substance grows less and less in size, and at
length, as happens with the yolk in the case of birds, the white
substance in the case of the young sepia disappears. In the case of
the young sepia, as in the case of the young of most animals, the eyes
at first seem very large. To illustrate this by way of a figure, let A
represent the ovum, B and C the eyes, and D the sepidium, or body of
the little sepia. (See diagram.)

Molluscs,

after pairing and copulation, lay a white spawn; and
this spawn, as in the case of the testacean, gets granular in time.
The octopus discharges into its hole, or into a potsherd or into any
similar cavity, a structure resembling the tendrils of a young vine or
the fruit of the white poplar, as has been previously observed. The
eggs, when the female has laid them, are clustered round the sides
of the hole. They are so numerous that, if they be removed they
suffice to fill a vessel much larger than the animal's body in which
they were contained. Some fifty days later, the eggs burst and the
little polypuses creep out, like little spiders, in great numbers; the
characteristic form of their limbs is not yet to be discerned in
detail, but their general outline is clear enough. And, by the way,
they are so small and helpless that the greater number perish; it is a
fact that they have been seen so extremely minute as to be
absolutely without organization, but nevertheless when touched they
moved. The eggs of the sepia look like big black myrtle-berries, and
they are linked all together like a bunch of grapes, clustered round a
centre, and are not easily sundered from one another: for the male
exudes over them some moist glairy stuff, which constitutes the sticky
gum. These eggs increase in size; and they are white at the outset,
but black and larger after the sprinkling of the male seminal fluid.

The so-called arctus or bear-crab lays its eggs at about the
same time as the crawfish; and consequently in winter and in the
spring-time, before laying their eggs, they are at their best, and
after laying at their worst.

They cast their shell in the spring-time (just as serpents
shed their so-called 'old-age' or slough), both directly after birth
and in later life; this is true both of crabs and crawfish. And, by
the way, all crawfish are long lived.

It lays its eggs

then, in this manner, and after hatching
them for about twenty days it rids itself of them all in one solid
lump, as is quite plain from outside. And out of these eggs crawfish
form in about fifteen days, and these crawfish are caught at times
less then a finger's breadth, or seven-tenths of an inch, in length.
The animal, then, lays its eggs before the middle of September, and
after the middle of that month throws off its eggs in a lump. With the
humped carids or prawns the time for gestation is four months or
thereabouts. Crawfish are found in rough and rocky places, lobsters in smooth
places, and neither crawfish nor lobsters are found in muddy ones; and
this accounts for the fact that lobsters are found in the Hellespont
and on the coast of Thasos, and crawfish in the neighbourhood of
Sigeum and Mount Athos. Fishermen, accordingly, when they want to
catch these various creatures out at sea, take bearings on the beach
and elsewhere that tell them where the ground at the bottom is stony
and where soft with slime. In winter and spring these animals keep
in near to land, in summer they keep in deep water; thus at various
times seeking respectively for warmth or coolness.