SPIDERS. 



141 



and in the case of some large species, even small birds fall victims 

 to its virulence. 



One peculiar characteristic of spiders, as we have already stated, 

 is the possession of a spinning apparatus, whereby the threads 

 composing their web are manufactured. The apparatus employed 

 for this purpose is situated upon the hinder part of the abdomen, 

 and consists externally of four spinnarcts, represented in the 

 accompanying figure. 



FIG. 149. SPINNING APPARATUS OF THE 

 SPIDER (greatly magnified). 



FIG. 148. GARDEN SPIDER. 



Each spinnaret when highly magnified is found to be perforated 

 at its extremity by innumerable orifices of exceeding minuteness, 

 through which the filaments are drawn. The fluid silk, which 

 constitutes the material whereof the thread is composed, is secreted 

 by a set of glands, situated in the interior of the body. Unlike 

 the single thread of a caterpillar, the thread of the spider, delicate 

 as it is, is known to be composed of hundreds of filaments, some- 

 times woven together by zigzag lines, and thus exhibiting a struc- 

 ture of exquisite and most elaborate composition. 



Various are the purposes to which the different species of 



