INSECTS AND THEIR NEAR RELATIVES. 35 



insects, and causing them to fall into the web, where they 

 are caught. 



Some of these spiders do not remain in their webs, but 

 have a nest in a neighboring crack or corner, from which 

 they rush to seize their prey. And sometimes there is a 

 funnel-shaped tube leading to this nest. But these spiders 

 differ from the true funnel- web weavers in running back down- 

 wards on the lower side of their web. 



Family Epeirid^e (E-pei'ri-dae). 

 The Orb Weavers, 



Few if any of the structures built by lower animals are 

 more wonderful than the nets of orb-weaving spiders, but 

 these beautiful objects are so common that they are often 

 considered hardly worthy of notice. If they occurred only 

 in some remote corner of the earth, every one would read of 

 them with interest. 



The nets of the different species of orb weavers differ in 

 the details of their structure, but the general plan is quite 

 similar. There is first a framework of supporting lines. The 

 outer part of this framework is irregular, depending upon the 

 position of the objects to which the net is attached; but the 

 more central part is very regular, and consists of a number 

 of lines radiating from the center of the net (Fig. 41). All 

 of these supporting lines are dry and inelastic. But there 

 is spun upon the radiating lines in a very regular manner a 

 thread which is sticky and elastic (Fig. 20, p. 23). Usually 

 this sticky thread is fastened to the radiating lines so as to 

 form a spiral, but a few species make nets in which this 

 thread is looped back and forth. 



Many of the orb weavers strengthen their nets by spin- 

 ning a zigzag ribbon across the center. This ribbon is made 

 by spreading the spinnerets apart so that the minute threads 

 from the spinning tubes do not unite to make a single thread, 

 as is usually the case. 



Some of the orb weavers live in their nets hanging head 



