SCORPIONIDEA 



521 



and pedipalps both chelate; four pairs of walking legs; the first 

 mesosomatic segment carries the genital operculum, the second the 

 pectines, and the next four each a pair of lung books; the metasoma 

 comprises segments reduced in size to form a flexible tail for wielding 

 the terminal sting (the telson) and bears no appendages. Viviparous. 



Fig. 356. Scorpio swammerdami, x f. From Shipley and MacBride. A, Dorsal, 

 B, Ventral view, chc. chelicera ; pp. pedipalp ; e.l. lateral and e.m.^ median 

 eyes; g.op. genital operculum; pet. pectines; 3, 4, 5, 6, walking legs of the 

 prosoma; 9, 10, 11, 12, stigmata of right side; 13, last segment of mesosoma; 

 pi. soft tissue of pleura ; met. i , first segment of metasoma ; tel. telson. 



The tergum of the prosoma bears a group of lateral eyes near the 

 anterior border and a pair of median eyes, but some scorpions are 

 blind. On the ventral surface there are inward projections from the 



