The wasps that are nicknamed 'the ichneumons' (or hunters), less
in size, by the way, than the ordinary wasp, kill spiders and carry
off the dead bodies to a wall or some such place with a hole in it;
this hole they smear over with mud and lay their grubs inside it,
and from the grubs come the hunter-wasps. Some of the coleoptera and
of the small and nameless insects make small holes or cells of mud
on a wall or on a grave-stone, and there deposit their grubs.

With insects, as a general rule, the time of generation from its
commencement to its completion comprises three or four weeks. With
grubs and grub-like creatures the time is usually three weeks, and
in the oviparous insects as a rule four. But, in the case of oviparous
insects, the egg-formation comes at the close of seven days from
copulation, and during the remaining three weeks the parent broods
over and hatches its young; i.e. where this is the result of
copulation, as in the case of the spider and its congeners. As a rule,
the transformations take place in intervals of three or four days,
corresponding to the lengths of interval at which the crises recur
in intermittent fevers.