ARACHNIDA 



449 



walking legs ; the first mesosomatic segment carries the genital oper- 

 culum, 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. 332. Scorpio swaynmerdami, 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 



basal joints of the pedipalps and the first two pairs of walking legs, 



Bi 29 



