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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 adheres to it, but it stretches so as to allow the insect 

 to become entano^Ied in other turns of the line. If it were not for 

 this elasticity of the sticky line most insects could readily te?vr 

 themselves away before the spider had time to reacli them. 



In running over its net, the spider steps upon t\]^ radii, carefully 

 avoiding the sticky line ; otherwise it would destroy its own net. 

 The rapidity with which a spider can cross its net without touching 

 the sticky line is remarkable. 



In making its web an orb weaver lirst 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 

 lirst line spun is a bridge between two quite distant points, as the 

 branches of two separate bushes. How did the spider cross the 

 gulf? It has no wings. 



Tiie bridge building can be easily seen on a warm summer even- 

 ing, the time at which the spiders are most active repairing their 

 old nets and building new ones. The spider lifts the hind end of its 

 body, and spins forth a thread ; this is carried off by the wind, until 

 finally striking some object it becomes fast to it. The spider then 

 pulls in the slack line, like a sailor, and when the line is taut fastens 

 it to the object on which it is standing, and the bridge is formed. 



After making the outward framework, the radiating lines are 

 formed. A line is stretched across the space so as to pass through 

 the point which is to be the center of the orb. In doing this the 

 spider may start on one side, and be forced to walk in a very round- 

 about way on the outer framework to the opposite side. It care- 

 fully holds the new line up behind it as it goes along, so that it 

 shall not become entangled with tiie lines on which it walks ; one or 

 both hind feet serve as hands in these spinning operations ; for as 

 the spider has eight feet, it can spare one or two for other pur- 

 poses than locomotion. AVlien the desired point is reached the 

 slack is pulled in and the line fastened. The spider then goes to 

 the point where the center of the orb is to be, and fastening another 



333 



