SCORl'lONS, SPIDERS, AND TICKS 



147 



reputation, but, with one exception, they are harmless and 

 among the most interesting animals in the worltl. 



Spiders have four pairs of legs and two pairs of jaws. At 

 the tip of each one of the larger jaws is a small hole, — 

 the opening of a poison gland through which the poison is 



Fig. 8.5. — Running spider : P, palpi ; H, ceplialotliorax ; A, abdomen. 



injected into the prey of the spider. Each member of the 

 small pair of jaws has attached to it a long, slender ap- 

 pendage called a palpus (plural, palpi) (Fig. 85). The 

 bodies of spiders consist of two parts, the cephalothorax 

 and the abdomen. They may have one, two, three, or 

 four pairs of single eyes, while certain ones living in caves 

 are blind. 



