290 



SCIENCE FROM AN EASY CHAIR 



of minute tubes, and hardens at once into a thread, which 

 is wonderfully fine, yet strong. 

 Different kinds of spiders make 

 use of these threads for differ- 

 ent purposes, hence their name 

 " spinners." Some make burrows 

 in the ground and line them with 

 a felt of these threads, others 

 enclose their eggs in a case 

 formed by winding them round 

 the eggs, others form "snares" 

 of the most marvellous mechani- 

 cal ingenuity with them, by which 



FIG. 48. View of the lower & * , , 



surface of the head and body msects are entangled and are 

 of a large Burmese spider, then paralysed by the poisonous 

 known as Liphistius, to show s tab of the spider's claws, and 



the spinnerets (3 and 4), which haye the}r ju j ces sucked out Qf 



are really reduced or rudi- , * .". 



mentary legs, and are in this them at the s P lder s leisure, 



spider retained in their original The snares of Spiders are in 



position, instead of being some species merely irregular 



t^" -* ^ened and suspended 



spiders (see Fig. 49, j/). I. to by threads, in other cases they 



VI., the basal joints of the legs are gracefully-modelled funnels 



and palps of the head-region; Qr , whilst a third kind, the 



I, the first abdominal seg- ,. ... , , /. ,. 



ment ; 2, the second ; 3 and 4, dlSC-llke webs made up of radl- 



the legs of the third and ating and circularly - disposed 

 fourth abdominal segments, threads fixed in a geometrical 

 which are the spinnerets ; ii, tt excel in the mechanical 



the eleventh abdominal seg- l . . ... 



ment-in front of it rudiments precision of their workmanship 

 of the segments 5 to 10 are and the masterly treatment of 

 seen ; an, anus ; a, b, inner engineering difficulties the con- 



and outer lobes of the first pair , . - . , . , c 



of spinnerets. structions of any other kind of 



animal. It is amongst this kind 



of spiders that the formation by the spinning knobs of 

 threads or lines and their use in various ways is most 



