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 manœuvres. 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 wisdom, 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 which she can clothe part 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
- [Footnote: *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 appeared 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 this time the old ones had nothing 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 woven, 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 round, 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 downwards. 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 of water, where it built a cell half under water, in which it laid its eggs."]
