Spiders and Their Near Relatives 



walking; they are seven-jointed, the tarsus consisting of three 

 segments, and the patella being wanting; the legs are not 

 chelate, but are furnished with tarsal claws. The coxae of the 

 first two pairs of ambulatory legs bear each an endite, which is 

 directed toward the mouth, and doubtless helps hold the prey 

 opposite the mouth (Fig. 22). 



The cephalothorax bears a pair of eyes near the middle 



line, the median eyes, and on each 

 side near the cepha.lo-lateral margin 

 a group of from two to five, the 

 lateral eyes. A few scorpions are 

 blind. 



Full-grown,, scorpions possess a 

 pair of comb-like organs, the pectines 

 (pec'ti-nes), on the lower side of the 

 second abdominal segment (Fig. 22). 

 The function of these organs is not 

 yet known, but it has been suggested 

 that it is tactile. " Pocock noticed 

 that a scorpion which had walked 

 over a portion of a cockroach far 

 enough for the pectines to come in 

 contact with it immediately backed 

 and ate it." 



Scorpions breathe by means of 

 book-lungs, of which there are four 

 pairs, opening on the lower side of the third to the sixth 

 abdominal segments. 



The sexes of scorpions differ in that the male has broader 

 pincers and a longer postabdomen. Scorpions do not lay eggs, 

 the young being developed within the mother; after the birth 

 of the young, the mother carries them about with her for some 

 time, attached by their pincers to all portions of her body. 



Scorpions live in warm countries. They are common in 

 the southern portion of the United States, but are not found 

 in the North. They are nocturnal, remaining concealed during 

 the day, but leaving their hiding places at dusk. When they 

 run, the pedipalps are carried horizontally in front, and are 

 used partly as feelers and partly as raptorial organs; and the 

 postabdomen is bent upward over the back by some, others 



Fig. 22. VENTRAL ASPECT OF 

 THE CEPHALOTHORAX AND TWO. 

 THE THIRD AND FOUR r H, AB- 

 DOMINAL SEGMENTS OF CEN- 

 TRURUS GRACILIS 



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