2o6 



FIRST LtSSONS IN ZOOLOGY 



many of them are small spiders sailing or " ballooning 

 through the air. These are called ballooning or aero- 

 nautic spiders. Examine carefully the top of fence-posts 

 or other exposed raised points and you may be fortunate 

 enough to discover one of these about to make an ascen- 

 sion (fig. 167). It will be standing with its legs close to- 

 gether and straight, the body being thus lifted as high as 

 possible, and the tip of the abdomen pointing upward. 



Fig. 167. — Ballooning spider ready to sail. (Natural size; after McCook.) 



From the spinnerets (at the tip of the abdomen) are issu- 

 ing lines floating freel}'. These lines are gradually spun 

 out (being really drawn out by the pull of the wind) until 

 they become so long that the wind bears them off with 

 the spider attacheil to them. Spiders may make long 

 journeys in tin's manner, and get themselves widel}' dis- 

 persed from their original habitat. These adventurers are 



