96 A NATURALIST IN HIMALAYA 



construct any more radii. The snare had eighteen in 

 position, and the spider, satisfied with this, passed 

 on to the next stage of its work. Such is the 

 persistence of the spider in the application of its radii. 

 In this snare that should have contained twenty-four 

 radii, the spider constructed eighteen together with 

 the twenty-five that I had severed. In all it laid down 

 forty-three instead of the normal twenty-four. From 

 this experiment we rest satisfied as to the mechanism 

 by which the spider tests its radii, and we see the 

 clear determination of the little architect to make 

 every radius secure. 



Such are the geometrical means by which the spider 

 constructs its radii. I pass now to consider if similar 

 methods are employed in the other features of its 

 work. The radii and hub are complete and the next 

 step in the architecture is the construction of the 

 temporary spiral. This binds the radii together. It 

 is the scaffolding of the snare. 



We again watch the workmanship. We again 

 discover the method of measurement ; the mathemati- 

 cal instinct on which the accuracy of the work depends. 

 Round goes the spider from radius to radius construct- 

 ing the first turn of its temporary spiral. Watch it 

 carefully at one radius. Its fore limb is applied to the 

 hub ; its spinnerets touch the radius and a definite 

 length is measured off along the radius ; the length 

 being the distance from the tip of the fore leg to the 

 spinnerets. Where the spinnerets meet the radius a 

 line is secured. The spider passes on to the next 

 radius. The same process occurs. The same length 

 is measured off on this radius. The fore limb again 

 finds the hub, the spinnerets again touch the radius 



