90 A NATURALIST IN HIMALAYA 



in addition giv^en it a special construction by which its 

 buoyancy is still more improved. 



In the Arancus it is difficult to detect this special 

 peculiarity of the first line. Little more can be seen 

 than the silken thread extending outward from the 

 spinnerets. But there is a large and handsome genus 

 of the geometrical spider known as Argyope, about an 

 inch in length, in which more detail can be seen. If 

 we have the chance to watch an Argyope in the act of 

 emitting the first filament of its snare, we will see that 

 the tip of the line that it gives to the wind is not 

 a single filament but a complex structure. It is 

 divided into a sheaf of the very finest fibrils, each 

 inconceivably light and delicate. These float freely in 

 the air and serve to support the more compact and 

 single thread that follows them from the spinnerets. 

 Thus the first filament of the snare is a highly 

 specialized thread, a long single line ending in a free 

 cluster of the finest, almost invisible fibrils ; a structure 

 beautifully adapted to sail on the wings of the faintest 

 breeze. Even the emission of the first line is worthy 

 of our note. It illustrates the ingenuity of the spider's 

 methods by employing the wind to support its lines, 

 and the exquisite adaptability of its filaments to the 

 varied stages of its work. 



I come now to the method by which the spider 

 constructs its radii ; a mode of workmanship that has 

 always filled me with wonder at the geometrical 

 powers of this simple creature. It is clear from the 

 beginning that the radii are laid down in no definite 

 order, but in a haphazard manner. Nevertheless they 

 are all equidistant ; all diverge from the common 

 centre with the same perfect synimetry as the spokes 



