94 A NATURALIST IN HIMALAYA 



tion-line, halts and anchors its filament. In this way 

 a radius of one strand is secured. But this is not 

 sufficient for the spider. The line must be of double 

 strength. The spider sets about it in this way. 

 It climbs back again to the centre of the snare, but 

 this time it makes its journey along the new radius 

 that it has just laid down. It pays out its filament 

 of silk behind it. It reaches the centre, draws tight, 

 anchors and secures its line. In this way the radius 

 is duplicated, and this gives additional strength to the 

 essential framework of the snare. 



I pass to the next stage of the architecture. The 

 radii are complete. In the snare I have just examined 

 they are twenty-four in number. The spider now 

 commences the next feature of its work. It winds 

 five turns of a slender filament around and close to 

 the centre, anchoring it at every spoke. Thus it con- 

 structs its hub. It does not always complete its radii 

 before commencing the hub. It may lay down a 

 few radii, then take a turn on the hub, then again 

 resume the radii. No doubt the hub helps to secure 

 the radii. But its construction has a greater value ; 

 for, as the spider circles five times round the centre 

 testing each radius in succession at every circle, it 

 satisfies itself repeatedly that all its radii are in place. 

 It examines with its dividers the position of each pair 

 of radii, and if they are not in accurate position it 

 proceeds to remedy the defect. 



An experiment will make this clear. A snare 

 is under construction. All the radii are in place. 

 The spider is engaged in the winding of its hub. 

 I divide one radius. The spider circles round and 

 reaches the gap made by the lost radius. It is 



