

Spiders have two pairs of jaws, wliicli, except in the Tarantula 

 family, move sideways like the jaws of insects. The first pair of 

 jaws are called the mandihles. Each mandible consists of two seg- 

 ments, a strong basal one and a claw-shaped terminal one, at the tip 



118. — Wasp, with head, 119. — Spider, showing cH- 120. — Lower side of cephalo- 



thorax and abdo- 

 men separated. 



vision of the body 

 into cephalothorax 

 and abdomen. 



thorax of a spider; md, 

 mandible; mx, maxilla; 

 \i, jxUpus ; ], loiter lip; 

 s, sternum. 



of which the poison gland opens (Fig. 120). The second pair of 

 jaws are known as the maxilla. These are situated just beliind the 

 madibles, one on each side of the mouth. Each maxilla bears a 

 large feeler or j)alj)us. These palpi vary greatly in form ; fre- 

 quently, especially in females, they resemble legs ; hence many 

 spiders appear to have five pairs of legs. In the male spiders the 

 last segment of the palpus is more or less enlarged, ending in a 



complicated knob-like structure (Fig. 

 121). It is thus easy to determine 

 the sex of a spider by merely exam- 

 ining the palpi. 



The greater number of spiders 

 have four pairs of eyes (Fig. 122), but 



there may be only one, two, or three 132.— ifm^Z of 



, ^ . . T spider, shoic- 



iMirs ; and certam cave spiders are . , 



J^ ' i mg eyes and 



blind. The eyes appear like little mandibles. 

 gems set in the front of the cephalothorax. They are most promi- 

 nent in the jumping spiders, which stalk their prey on plants^ ^^8'^> 

 fences, and tlie sides of buildings. 



121. — Maxilla and 

 palpus of male 

 house spider. 



U'jy 



