36 



THE STUDY OF AV SECTS. 



downwards, usually near the center of the net ; others have 

 a retreat near one edge of the net, in which they hang back 



Fig. 41. — Partially completed web of Epeira. 



downwards. While resting in these retreats they keep hold 

 of some of the lines leading from the net, so that they can 

 instantly detect any jar caused by an entrapped insect. 



When an insect in its flight touches one of the turns 'of 

 the sticky line, the line sticks to it ; but it stretches so as to 

 allow the insect to become entangled in other turns of the 

 line. If it were not for this elasticity of the sticky line, most 

 insects could readily tear themselves away before the spider 

 had time to reach them. 



In making its web an orb weaver first spins a number of 

 lines extending irregularly in various directions about the 

 place where its orb is to be. This is the outer supporting 

 framework. Often the first line spun is a bridge between 

 two quite distant points. This is done as described on p. 25. 

 Having a bridge across the place where the web is to be, it 

 is an easy matter for the spider to stretch its other lines 

 where it wishes them. In doing this it fastens a thread to 

 one point, and then walks along to some other point, spin- 



