272 INSECT WATER TRESPASSERS. 



the legs, and at once dives. If watched, it will be 

 seen to have stretched its last pair of legs well be- 

 hind the body, and by their aid to have inclosed a 

 large bubble of air, which completely envelopes the 

 abdomen. Burdened for it is a burden with this 

 bubble of air, the Spider dives with manifest exertion, 

 and is lost to sight. 



Not that when it dives it always takes this air- 

 bubble with it. In fact, as a general rule, it dives 

 without the large bubble, and only has its body 

 studded with the minute bubbles which have already 

 been mentioned. They completely alter the Spider's 

 appearance. 



Out of the water the Spider has nothing con- 

 spicuous about it, and no one who did not know the 

 creature would ever suspect that it had anything in its 

 mode of life which distinguished it from other spiders. 

 But, as soon as it dives, the multitudinous air-bubbles 

 which surround the body make it look exactly as if it 

 were clothed in an envelope of quicksilver globules, 

 which have a curiously glittering appearance as the 

 Spider descends into the water. 



The generic name, Argyronetra, refers both to the 

 appearance and the shape of the body. It is com- 

 pounded of two Greek words, the former signifying 

 silver, and the latter a spindle. This name is given to 

 it in consequence of the form of the body, which ends 

 in a point, and is altogether of a spindle-like shape. 

 If I wished to use strictly scientific language, I should 

 say that the generic name of the Spider was given to 

 it because its body was fusiform ; but I prefer to 

 express the same idea in simple English terms. 



