TRUE SPIDERS 



407 



spinning mamilke or spinners, through hundreds of extremely fine tubes, 

 the spinnerets. Out of each of these tubes flows a drop of this silk 

 matter, which by the movement of the spider is drawn out into a fine 

 thread. The threads of the spinnerets unite, and, soon hardening, form 

 a strong and firm silk line. Yet when all the glands are active, and silk 

 flows from all the tubes, the thread which is formed is, in comparison 

 with a human hair, as a strand of spun-yarn in comparison with a rope. 

 Being composed of a, large number of fibres, the spider's thread not 

 only hardens very rapidly in the air, but also acquires a wonderful 



R. 



UNDER SIDE OF ABDOMEN OF A GARDEN SPIDER 

 WITH SPINNERS. (Strongly magnified.) 



v.W., m.W., h.W., Anterior, middle and posterior 

 spinners bearing on their surface numerous spin- 

 nerets. (Between the two anterior papillae is a 

 small conical body, the spindle, Sp., whose func- 

 tion is unknown.) 



ONE OF THE MEDIAN SPINNING 

 ORGANS (MAMILL^I) IN ACTION. 

 (More strongly magnified.) 



ra.W., The mamilla ; ft., two stout and 

 numerous fine spinnerets ; F. , fibres 

 of silk emitted from spinnerets. 



firmness and uniformity of structure. (Explain this more fully. 

 Which is stronger, an iron rod or a wire rope of the same thickness ? 



(e) Very dexterously the spider runs about over its web, only the tips 

 of its legs touching the threads, and, which seems very remarkable, the 

 creature never becomes enmeshed in the web like the flies and gnats, 

 nor does it tear a single one of the delicate fibres. This is due to the 

 fact that the animal .walks exclusively on the pectinated claws of its feet, 

 which, being very smooth, can be hooked into and lifted out from the 



