THE WATEK SPIDER. 665 



its life in the water, and for the greater part of its time is submerged 

 below the surface. To a lesser degree several other spiders lead a some- 

 what similar life, sustaining existence by means of the air which is en- 

 tangled in the hairs which clothe the body. Their submerged existence 

 is, however, only accidental, while in the Water Spider it forms the con- 

 stant habit of its life. 



The body of the Water Spider is profusely covered with hairs, which 

 serve to entangle a large comparative amount of atmospheric air, but 

 it has other means which are not pos- 

 sessed by the species already described. 

 It has the power of diving below the 

 surface and carrying with it a very 

 large bubble of air that is held in its 

 place by the hind legs ; and in spite of 

 this obstacle to its progress, it can pass 

 through the water with tolerable speed. 



The strangest part in the economy 

 of this creature is that it is actually 

 hatched under water, and lies sub- 

 merged for a considerable time before ^^^ ^^^^^ g^^^^^ (Argyrone. 



it ever sees the land. At some little 



tra aquatica) 



depth the mother spider spins a kind 

 of egg or dome-shaped cell with the opening downward. Having 

 made this chamber, she ascends to the surface, and there charges her 

 whole body with air, arranging her hind legs in such a manner that 

 the bubble held between them cannot escape. She then dives into the 

 water, proceeds to her nest, and discharges the bubble into it. A quan- 

 tity of water is thus displaced, and the upper part of the cell is filled 

 with air. She then returns for a second supply, and so proceeds until 

 the nest is full of air. 



In this curious domicile the spider lives, and is thus able to deposit 

 and to hatch her eggs under the water without even wetting them. 

 The reader will have noticed the exact analogy between this subaquatic 

 residence and the diving-bell, now so generally employed. As to the 

 spider itself, it is never wet ; and, though it may be seen swimming 

 rapidly about in the water, yet the moment it emerges from the sur- 

 face its hairy body will be found as dry as that of any land spider. 

 The reason for this phenomenon is that the minute bubbles of air 

 which always cling to the furred body repel the water and prevent it 

 from moistening the skin. 



The eggs of tliis spider are enclosed in a kind of cup-shaped cocoon, 

 not unlike the cover of a circular vegetable-dish. This cocoon usually 

 contains about a hundred little spherical eggs, which are not glued 

 together. 



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