SPIDERS. 151 



All Spiders secrete a poisonous fluid, which is, no doubt, for- 

 midable and even fatal to insects, though it produces but little 

 effect on the human frame. The poison is conveyed through 

 a perforated fang in the mandibles. In the Scorpion (Fig. 1 45 ), 



Fig. 145. SCOHPION. 



on the contrary, it is lodged in the extremity of the slender 

 flexible tail, and the wound is inflicted by the recurved sting 

 by which the tail is terminated. 



Spiders have another secretion, still better known; that 

 which furnishes the material of which their threads are com- 

 posed. The little teats, whence the threads proceed,, arc at 

 the hinder extremity of the body, and are four, six, or eight 

 in number. Each of these is composed of orifices so fine, that 

 Leeuwenhoek and other eminent microscopic observers have 

 regarded a Spider's thread, even when so fine that it is almost 

 imperceptible to our senses, not as a single line, but as a rope 

 composed of at least four thousand strands. From Mr. 

 BlackwalFs observations, there is reason to think that this 

 estimate is too high, and that the total number of the papilla, 

 whence the lines proceed, does not greatly exceed a thousand ; 

 yet, even admitting this to be the case, our wonder at the 

 complex structure of a Spider's thread is scarcely lessened.* 



That any creature could be found to fabricate a net, not less 

 ingenious than that of the fisherman, for the capture of its 

 prey; that it should fix it in the right place, and then patiently 

 await the result, is a proceeding so strange, that if we did not 

 sec it done daily before our eyes by the common House-spider 

 and Garden-spider, it would seem wonderful; but how much 

 is our wonder increased when we think of the complex fabric 



* Trans. Linn&nn Society, vol. xvi. page 220, 

 PAUT. i. II 



