44 



BUTHID^. 



Jently by Plesiobuthus and Isometrus, the former being a de- 

 scendant of Buthus and the latter of Lycfias, it will be difficult 

 to find valid reasons for upholding the groups Butbinae and 

 Centrurinae. 



31. Plesiobuthus paradoxus, sp. n. 



Colour mostly a fairly uniform yellow ; ocular tubercle and 

 frontal area of carapace infuscate ; middle line of tail and its 

 superior and supero-lateral crests, as well as the sides of the 



vesicle and the three inferior 

 C. B. A. keels of the 5th caudal seg- 



ment, infuscate ; chelae and 

 legs yellow, with keels infus- 

 cate. Carapace as long as 

 the 5th caudal segment ; finely 

 granular. Terr/a closely gran- 

 ular. Sterna smooth, finely 

 granular at the sides ; the 

 last with two granular crests, 

 the median pair being obso- 

 lete. Tail about five and a 

 half times as long as the 

 carapace, the first three seg- 

 ments subequal in width, 

 4th much narrower than 3rd 

 and 5th than 4th ; median 

 lateral keel present only on 

 the posterior half of the 1st 

 segment, absent on the rest ; 

 inferior median keels smooth on segments 1 and 2, scarcely 

 granular on 3 and 4; the rest of the keels granular: intercarpal 

 spaces of tail smooth, or at most finely granular; reside narrower 

 than 5th segment, smooth, punctured below ; aculeus long and 

 lightly curved. Chela' with humerus, brachium, and hand granu- 

 larly crested ; hand wider than brachium ; underhand about half 

 the length of the movable digit ; movable digit much longer than 

 earapace, armed with 11 rows of teeth. Leys with femora and 

 patellae armed with granular crests. Pectines long, furnished with 

 37 teeth. 



Measurement's in mm. — Total length 56, carapace 6, tail 34, 

 movable digit 6*5. 



Loc. Northern Baluchistan (Maynard 6f MarMalton). 



Fig. 11. — Plesiobuthus paradoxus. 



A. Extremity of 3rd leg, from above. 

 B. Ditto, from the side. 0. Vesicle 

 and aculeus. 



Genus ISOMETRUS, Eempr. & Ehrenb. 



[sometrus, Hempr, 8f Ehr. Symb. Phys., Seorp. p. •"!, L828; also 

 of Thorrll, Karsch, Simon, Pocock, etc. (in part) prior to L891; 

 Kraepelin, Jb. Hamb. iri.ss. And. viii, p. 244, 1891, and of 

 subsequent authors. 



Terga of carapace with only a median keel. Tail with a large 



