FOOD or INSECTS. 



339 



All spiders do not spin webs. A considerable number 

 adopt other means for catching insects. Of these I shall 

 speak hereafter. At present I shall endeavour to give you a 

 clear idea of the operations of the weavers, explaining suc- 

 cessively the instruments by which they spin, the mode of 

 forming their nets, together with the various descriptions of 

 them, and the manner in which they entrap and secure their 

 prey. 



The thread spun by spiders is in substance similar to the 

 silk of the silk-worm and other caterpillars, but of a much 

 finer quality. As in them, it proceeds from reservoirs, into 

 which it is secreted in the form of a viscid gum ; but in the 

 mode of its extrication is very dissimilar, issuing not from 

 the mouth, but the hinder part of the abdomen. If you 

 examine a spider, you will perceive in this part four or six 

 little teat-like protuberances or spinners. These are the 

 machinery through which, by a process more singular than 

 that of rope-spinning, the thread is drawn. Each spinner is 

 furnished with a multitude of tubes, so numerous and so 

 exquisitely fine, that a space often not much bigger than the 

 pointed end of a pin, is furnished, according to Reaumur 

 with a thousand of them. From each of these tubes, con- 

 sisting of two pieces, the last of which terminates in a point 

 infinitely fine, proceeds a thread of inconceivable tenuity, 

 which, immediately after issuing from it, unites with all the 

 other threads into one. Hence from each spinner proceeds 

 a compound thread ; and these four (or six) threads, at the 

 distance of about one tenth of an inch from the apex of 

 the spinners, again unite, and form the thread we are accus- 

 tomed to see, which the spider uses in forming its web. The 

 threads, however, are not all of the same thickness, for Leeu- 

 wenhoek observed that some of the tubes were larger than 



1 Reaum. Mem. de VAcad. de Paris, An. 1713. 211. — De Geer, vii. 187. 

 See also Hoole's Leeuwenlioek, i. 41. — t. 2. f. 20 — 22. Leeuwenhoek examined 

 a spinner that was not so big as a common grain of sand, and the number of 

 tubes issuing from it was more than a hundred. He affirms that, besides the 

 larger spinners, in the space between them there are four smaller ones, each fur- 

 nished with organs for spinning threads, but smaller and fewer in number. 

 Latreille speaks only of a thousand spinners from each teat, and of six thousand 

 threads from the whole — but he does not enter further into the subject. Nouv. 

 Diet. d'Hist. Nat. ii. 278. 



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