THE ARACHNIDA. 



AA7 



The engraving represents some of the spiders on the floating 

 leaves, and one has made its plunge into the water. The cephalo- 

 thorax is white, because the fine silky covering of web which 

 encases the body contains air ; and the whole of the spiders 



THE NESTS OF THE WATER SPIDER. {Argyroneta aquatka.) 



which are seen deep in the water are of the same colour, because 

 air is mechanically entangled in the tissue covering the whole 

 of their bodies. This air is rubbed off with the aid of the legs 

 when the spider enters its bell-shaped nest, and its globules replace 

 the water, and at last, after successive ascents and descents, the 

 dome is full of air. 



