XXXIV. INTKODTTOTION. 



that, as a rule, the life of a spider soon closes when its eggs are 

 laid, or its young hatched and able to shift for themselves. In 

 most cases the males disappear very quickly after the impregna- 

 tion of the females ; but without a doubt some of our house- 

 spiders— as Tegenaria and Amaurobius — will, under favourable 

 circumstances, live for more than one season, perhaps for even 

 several years. Mr. Blackwall states (Spid. Great Brit and Irel., 

 p. 8) that Tegenaria civilis, and Segestria senoculata have been 

 proved to live for four years. The subject, however, of the 

 duration of life among spiders is involved in much obscurity, 

 owing to the difficulty of making any trustworthy observations 

 upon it. 



Classification of Spiders. 



This portion of the subject must not bo passed over, though 

 it cannot be gone into at any great length. 



One of the first things that a Natural History collector desires 

 to knowsomething about is, how to arrange scientifically the objects 

 of his study. Now, in respect to spiders, there is, of course, the 

 same basis of classification, as there is in regard to every other 

 Natural group. Form, structure, colours, and markings, and, in a 

 lesser degree, size, are the chief characters upon which all classifica- 

 tion is based. The true spiders — Araneidca — form a remarkably 

 homogoneous group of tho Great Branch of the Animal Kingdom 

 — Articulata ; and constitute one out of the seven orders of the 

 class Arachnida. 



The basis of the classification of spiders has already been 

 touched upon, in defining what a spider is, and in distinguishing 

 it as well from insects, as from the members of the collateral 

 orders — Acaridea, Phalangidea, and Scorpionidea. It will suffice, 

 therefore, to diagnose shortly tho Arachnida generally, and the 

 order Araneidoa, which we are at present treating upon. 

 Perhaps the following diagram will be useful, as giving a 

 general idea of tho whole subject : — 



