THE SPIDER. 149 



throw out isolated threads, connecting their lair with 

 the edges of the trap ; in this case, as soon as an unfor- 

 tunate fly touches the web the scarcely-perceptible shock 

 is communicated by the conducting threads to the spider, 

 who rushes out and strangles his prey by enveloping it 

 with new threads, at the same time paralyzing it by 

 the thrust of a poisonous dart with which the end of 

 his jaw is armed. Then he fixes himself on his immobile 

 victim, sucking the juices and humors, and abandoning 

 the cadaver only when it is reduced to a dry and empty 

 shell. 



Spiders eat their kind : two of these creatures put 

 together begin a mortal combat, and the vanquished is 

 eaten by the victor. This natural ferocity has been the 

 cause of the failure of all efforts to raise colonies of 

 spiders, efforts undertaken with the object of utilizing 

 their silky secretion, which is analogous to that of the 

 silk-worm. 



The buccal apparatus of the spider is very powerful ; 



FIG. 83. 



m 



CEPHALOTHORAX OF SPIDER, FROM THE SIDE. c, claws; pm, jaws; pi, p 2 , the 

 first two feet ; g, hooks. 



it consists of a pair of mandibles or forceps having 

 two joints. The upper one is a sharp hook, very hard, 

 and having near its point a hole for the projection of a 



13* 



