THE MYRIAPODS AND ARACHNIDS 



79 



overcome a large insect caught in their snares, many orb 

 weavers make another use of their web in spinning a 

 broad sheet of it around their captive until its struggles 

 are effectually overcome. Then the spider sucks out 

 its victim's blood and frequently ejects the carcass 

 from its snare. 



Another interesting use of web is in " ballooning" 



which is a common prac- 

 tice among young spiders. 

 The spider when preparing 

 for its journey through the 

 air mounts upon a promi- 

 nence and shoots out a 

 quantity of web which is 



FIG. 65. Attitude of aeronautic 

 spider just before taking flight. (After 

 McCook.) 



FIG. 66. Ballooning spiders 

 floating in air by means of masses 

 of web. The spider at the right 

 is gathering in its web in order to 

 descend. (After McCook.) 



caught by the wind and pulled out further; finally the 

 spider lets go its hold and is carried away with the float- 

 ing mass of web that is wafted by the wind. Spiders may 

 travel for miles in this way. When they wish to descend 

 they haul in the web until they slowly sink to the ground. 

 There are many spiders which actively hunt for their 



