HABITATIONS OF INSECTS. 267 
diameter, forming a cylindrical bag of dark-coloured silk, closed at the 
bottom, and accurately fitted at the top by a door or lid.* 
The habitation of Argyroneta aquatica, the other spider to which I 
alluded, is chiefly remarkable for the element in which it is constructed and 
the materials that compose it. It is built in the midst of water, and formed, 
in fact, of air! Spiders are usually terrestrial, but this is aquatic, or rather 
amphibious; for though she resides in the midst of water, in which she 
swims with great celerity, sometimes on her belly, but more frequently on 
her back, and is an admirable diver, she not apheeeuanely hunts on shore, 
and having caught her prey, plunges with it to the bottom of the water. 
Here it is she forms her singular and unique abode. She would evidently 
have but a very uncomfortable time were she constantly wet, but this she 
is sagacious enough to avoid; and by availing herself of some well-known 
hilosophical principles, she constructs for herself an apartment in which, 
ike the mermaids and sea-nymphs of fable, she resides in comfort and 
security. The following is her process, First she spins loose threads in 
yarious directions attached to the leaves of aquatic plants, which may be 
called the frame-work of her chamber, and over them she spreads a trans- 
parent varnish resembling liquid glass, which issues from the middle of her 
spinners, and which is so elastic that it is capable of great expansion and 
contraction ; andif a hole be made in it, it immediately closes again. Next 
she spreads over her belly a pellicle of the same material, and ascends to 
the surface. The precise mode in which she transfers a bubble of air 
beneath this pellicle is not accurately known; but from an observation 
made by the ingenious author of the little work from which this account is 
abstracted, he concludes that she draws the air into her body by the anus, 
which she presents to the surface of the pool, and then pumps it out from 
an opening at the base of the belly between the pellicle and that part of the 
body, the hairs of which keep it extended. Clothed with this aérial mantle, - 
which to the spectator seems formed of resplendent quicksilver, she plunges 
to the bottom, and, with as much dexterity as a chemist transfers gas with 
a gas-holder, introduces her bubble of air beneath the roof prepared for its 
reception. This manceuvre she repeats ten or twelve times, until at length 
in about a quarter of an hour she has transported as much air as suffices 
to expand her apartment to its intended extent, and now finds herself in 
possession of a little aérial edifice, I had almost said an enchanted palace, 
affording her a commodious and dry retreat in the very midst of the water. 
Here she reposes unmoved by the storms that agitate the surface of the 
ool, and devours her prey at ease and in safety. Both sexes form these 
odgings, At a particular season of the year the male quits his apartment, 
approaches that of the female, enters it, and enlarging it by the bubble of 
ar that he carries with him, it becomes a common abode for the happy 
pair? The spider which forms these singular habitations is one of the largest 
European species, and in some countries not uncommon in Hears pools. 
am, &¢c. 
1 See several Memoirs upon this ard some allied species by Messrs. Sells, 
Saunders, and Westwood, in the Z'rans. of the Ent. Soc. of London, vols. ii. and iii. 
® Mémoire pour servir d commencer U Histoire des Araignées Aquatiques, 12mo 
