doubtless, is a question of acclimation. I advise white oak (_Quercus
alba_) as food, if it can be readily obtained, but failing that, pin
oak (_Quercus palustris_) will do; and I have no doubt that they will
feed on any kind of oak. They will, indeed, feed on birch, and on
sweet gum (_Liquidambar_), but oak is the proper food. It is worthy of
remark that _Pernyi_ bears a strong resemblance to our _Polyphemus_,
but it is more easily reared in confinement, and double brooded; an
important fact for the silk culturist. From American reared eggs, I
obtained cocoons as early as July 4th, the perfect insect emerging on
July 31. Copulation immediately ensued, and the resulting eggs hatched
only on August 12, ten days only from the time of laying; and as the
worm feeds up in about four or five weeks, this affords plenty of
time for rearing the second brood. It must be remembered that on the
quantity and quality of food, much depends, not only with _Pernyi_
but with all caterpillars. By furnishing food sparingly the time of
feeding would be much prolonged.

I have already said that both _Yamamai_ and _Pernyi_ should be fed
under shelter for the reasons given, but there is another reason of
less importance. The young worms are liable to be attacked by spiders
and wasps, and even after the second month, they are not safe from
these enemies. I have seen a wasp bite a large caterpillar in two,
carry off the anterior section and return for the posterior, which
had held on by its prolegs. Did the wasp anticipate this fact, and
therefore carry off the anterior part first? As to the spiders, they
form a series of pulleys and hoist the caterpillar off its legs,
sucking its juices at leisure.

And now I must devote a few words to the advisability of silk culture
from a pecuniary point of view. _Bombyx mori_, or the ordinary
mulberry silkworm, is, of course, the best to rear, if you can obtain
healthy eggs. But this is the difficulty, and thence arises the
necessity of cultivating other silk-producing species. I imagine
that silk can be produced in most of the States of the Union, and
manufactured from the cocoon at a large profit; but for the present,
we will leave the manufacture out of the question, and consider only,
whether it will not pay to rear eggs and cocoons for sale? It must
be remembered that European manufacturers are at this moment largely
dependent on foreign countries for the supply of both eggs and
cocoons; and this,