SPIDERS 41 



mature males the pedipalps are highly modified in connection 

 with the reproductive functions. The basal joint of these limbs 

 carries a blade-like expansion, " maxilla," on its inner face, and the 

 two maxillae can meet across the mouth, which is very small ; 

 these processes are used to squeeze the juices out of the body of 

 victims into the spider's mouth. No solid food is swallowed. 

 The dorsal portions of the pedipalps are more or less hairy, like 

 the legs, and doubtless both 

 these sets of limbs perform 

 delicate sensory functions, and 

 thus compensate for the ab- 

 sence of antennae. Behind the 

 pedipalps come the four pairs 

 of true walking leers, whose 



' . FIG. 23. Pedipalp of a male spider. 



number is as constant m the 



spiders as are the three pairs in insects. Each leg is composed 

 of seven joints, and terminates in two or in three curved claws 

 which are generally pectinated (provided with comb-teeth). In 

 some spiders the penultimate joint of the last leg bears a long 

 series of closely set bristles (the calamistrum) which are used for 

 teasing out a peculiar kind of silk produced from the extra 

 " spinner " possessed by such species. This silk becomes, when 

 so treated, very fluffy and adhesive, and is then spread on the 

 other strands of the snare. 



The eyes are placed on the front region of the cephalo-thorax, 

 sometimes on its dorsal, sometimes on its anterior surface, some- 

 times on both. They are usually eight, though 

 in some only six in number ; they cannot be 

 moved, nor are they compound like those of 

 insects. Their relative sizes and positions differ 

 FIG. 24. Dorsal view g rea ^Y m various species, so much so that these 

 of head of garden features are of great importance in the classifica- 



spider, showing the -j-j Qn Q spiders. 



arrangement of the ,~, , , . . 



eyes Ine abdomen is always soft and unseg- 



mented, but exhibits great diversity of shape. 



On its ventral surface, just behind the waist, is a small plate, 



generally notched in its middle, which is the lid covering the 



genital opening. The plate represents two abdominal appendages 



