212 
ANIMAL INTELLIGENCE. 
The position must also offer favourable opposite points for the 
attachment of the web itself. People have often puzzled their 
brains, wondering how spiders, without being able to fly, had 
managed lirst to stretch their web through the air between two 
opposite points. But the little creature succeeds in accomplish- 
ing this difficult task in the most various and ingenious ways. 
It either, when the distance is not too great, throws a moist 
viscid pellet, joined to a thread, which will stick where it 
touches ; or hangs itself by a thread in the air and lets itself be 
driven by the wind to the spot ; or crawls there, letting out a 
thread as it goes, and then pulls it taut when arrived at the 
desired place ; or floats a number of threads in the air and 
waits till the wind has thrown them here or there. The main 
or radial threads which fasten the web possess such a high 
degree of elasticity, that they tighten themselves between two 
distant points to which the spider has crawled, without it being 
necessary for the latter to pull them towards itself. When the 
little artist has once got a single thread at its disposition, it 
strengthens this until it is sufficiently strong for it to run back- 
wards and forwards thereupon, and to spin therefrom the web. 1 
Special Habits . 
Water-spider . — The water-spider ( Argyvoneta aqua - 
tica\ as is well known, displays the curious instinct of 
building her nest below the surface of water, and construct- 
ing it on the principle of a diving-bell. The animal 
usually selects still waters for this purpose, and makes 
her nest in the form of an oval hollow, lined with web, 
and held secure by a number of threads passing in various 
directions and fastened to the surrounding plants. In 
this oval bell, which is open below, she watches for prey, 
and, according to Kirby , 2 passes the winter after having 
closed the opening. The air needful for respiration the 
spider carries from the surface of the water. To do this 
she swims upon her back in order to entangle an air- 
bubble upon the hairy surface of her abdomen. With this 
bubble she descends, 6 like a globe of quicksilver,’ to the 
opening of her nest, where she liberates it and returns fo? 
more. 
1 Log . cit ., p. 316 et seq. 
2 Hist. Habits and Inst, of Animals, vol. ii., p. 296. 
