86 A NATURALIST IN HIMALAYA 



foundation-line the spider adopts a different procedure. 

 It takes its stand about midway on the first Hne and 

 suddenly drops down suspended on a filament of silk. 

 Perhaps it finds an attachment. If not, it climbs up 

 again and drops down from another point. At length 

 it meets a blade of grass and anchors its second line. 

 It has now two lines with three attachments to stalks 

 of grass, one at each end of the first line and one at 

 the lower end of the second line. By joining these 

 points together with a filament of silk a triangle is 

 formed of three foundation-lines, the simplest form of 

 framework to support a geometrical snare. The 

 spider reinforces these lines with additional filaments 

 until it is satisfied with the strength of the scaffold. 

 This is the first and elemental stage ; the construction 

 of the foundation-lines. 



I now come to the second step in the architecture. 

 A triangular framework is in position ; or, if suitable 

 connections can be found, a trapezoid figure is more to 

 the spider's choice. Whatever its shape, the spider 

 next proceeds to construct the radii. These are the 

 spokes of a wheel that diverge from a common centre 

 to end at the foundation-lines. The spider constructs 

 them with little trouble. It first runs a line from side 

 to side across the framework. Then, selecting a point 

 on that line which will be the future centre of the 

 snare, it carries a number of lines from that central 

 point to the circumference of the snare. In this way 

 it completes a series of radii, each equidistant from its 

 adjoining radius. Each radius is in accurate position ; 

 all diverge equally from the common point. The 

 second stage is mathematically complete. 



Now comes the third stage, the construction of a 



