MASON SPIDERS. DIVING SPIDERS. 137 



and of Southern Europe, which to the mouth of its retreat (an 

 excavated subterranean cell, tapestried with silk) contrives to 

 adjust an earth-kneaded door, hung upon a silken hinge, and 

 self-closing with an elastic spring, after each entrance and exit 

 of the cavern's occupant. 



For description in full of this foreign master-piece of 

 Arachnean architecture we must refer to other pages,* and 

 pursuing the main purpose of our own, invite attention to the 

 constructive skill of one more native Spider. 



Who has not seen, or is not curious to behold that " lion" 

 of the Polytechnic, the diving-bell ? Now those who for lack 

 of opportunity are among the latter, may see a diving-bell in 

 miniature by repairing to the brink of some running stream, 

 canal, or ditch (provided it be not stagnant), in the neighbour- 

 hood of London or elsewhere. There they may perceive, 

 shining through the water, a little globe apparently of silver, 

 which surrounds as with a garment, the body of a Diving Spi- 

 der,! whose submerged habitation and curious economy have 

 been described, as follows, by different observers. "These 

 Spiders," says De Geer, " spin in the water a cell of strong 

 closely woven white silk, in the form of a diving-bell or half a 

 pigeon's egg. This is sometimes quite submerged ; at others 

 partly above the water, and is always attached to some objects 

 near it by a number of irregular threads. It is closed all round, 

 but has a large opening below, which however I found closed 



* See Insect Architecture. t Diving Water-Spider, Argyroneia aquatica. 



