The Life of Spiders 



spinnerets are then applied to the next radius and the thread 

 fastened in place; after which the spider takes away its hind leg 

 and the thread contracts to the length of the space between the 

 two radii. In Fig. 192 the fine threads of the attachment disk 

 connecting the viscid thread to the radius can be seen. 



The pulling out of the viscid line by the hind leg before it 

 is fastened between two radii leaves it relaxed when put in place; 

 so that it can be easily stretched by an entangled insect, and 

 thus ensures the insect being caught in other turns of the viscid 

 spiral. 



Fig. ig 2 . FROM A PHOTOMICROGRAPH OF A RADIUS AND A VISCID LINE 



The free lone— -The viscid spiral is not continued entirely 

 to the notched zone, an area of greater or less width being left, 

 free from any spiral line; this is termed the free {one. In some 

 webs this feature is not conspicuous, but in others the free zone 

 is of considerable width and furnishes a means by which the 

 spider can pass freely from one side of the web to the other. 



The stabilimentum. — Some of the orb-weavers strengthen 

 their webs by spinning a zigzag ribbon across the centre or below 

 the hub (Fig. 188). This ribbon has been termed the stabili- 

 mentum. It consists of a large number of minute threads resem- 

 bling the swathing band and is doubtless spun from the small 

 spinning tubes of either the p\ riform or of the aciniform glands. 



203 



