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.