The history of silk, cotton, linen, wool, and other fibrous ... - Cd3wd.com

170 CULTIVATION AND MANUFACTURE OF SILK.
equal mass of water, again ascends for a second lading, till
she has sufficiently filled her house with it, so as to expel all
the water.
" The males construct similar habitations by the same ma-
noeuvres. How these little animals can envelope their abdomen
with an air-bubble, and retain it till they enter their cells,
is still one of Nature's mysteries that have not been explained.
" We, however, cannot help admiring, and adoring, the vns-
dom, power, and goodness manifested in this singular provision,
enabling an animal that breathes the atmospheric air, to fill
her house with it under water, and which has instructed her in
a secret art, by ichich she can clothe jiart of her body with air
as a garment, and which she can put off when it answers her
purpose.
" This is a kind of attraction and repulsion which mocks all our inquiries."
Thus it appears, that by the successive descents of the little
water-spider under the impulsion of its instinct, produce effects
males began to stretch diagonal threads in a confused manner from it to the sides
of the glass about half way down. Each of the females afterwards fixed a close
bag to the edge of the glass, from which the water was expelled by the air from
the spinneret, and thus a cell was formed capable of containing the whole animal.
Here they remained quietly, with their abdomens in their cells, and their bodies
still plunged in the water ; and in a short time brimstone-colored bags of eggs ap-
peared in each cell, filling it about a fourth part. On the 7th of July several
young ones swam out from one of the bags. All tliis time the old ones had no-
thing to eat, and yet they never attacked one another, as other spiders would have
been apt to do (Clerck, Aranei Suecici, cap. viii.)."
" These spiders," says De Geer, " spin in the water a cell of strong, closely wo-
ven, white silk in the form of half the shell of a pigeon's egg, or like a diving bell.
This is sometimes left partly above water, but at others is entirely submersed, and
is always attached to the objects near it by a great number of irregular threads.
It is closed all romid, but has a large opening below, which, however, I found
closed on the 15th of December, and the spider living quietly within, with her
head dowmwards. I made a rent in this cell, and expelled the air, upon which
the spider came out ; yet though she appeared to have been laid up for three
months in her winter quarters, she greedily seized upon an insect and sucked it.
I also found that the male as well as the female constructs a similar subaqueous
cell, and during summer no less than in winter (De Geer, Mem. des Insectes, vii.
312.)." " We have recently kept one of these spiders," says Mr. Rennie, " for
several months in a glass ol water, where it built a cell half under water, iu which
it laid its eggs."