128 MR. R. J. pococK ON THE SCORPIONS [Mar. 18, 



vesicle either with or without a tubercle 



beneath the aculeus Subgenus Geosphus, Simon. 



Type G. madagascariensis (Gerv.). 

 c^. The basal pectinal tooth in the female like 

 the rest ; tail powerful and as a rule 

 strongly keeled; without a spme or tubercle 



beneath the aculeus . Subgenus Parabuthus, n. 



Type P. liosoma (Ehrb.). 

 d^. Tergites with a single median and two lateral 

 keels ; cephalothorax, as a rule, distinctly 

 keeled. 

 /'. Fifth caudal segment with rounded supero- 

 lateral edges Subgenus BuTnus (s. s.)- 



Type B. europcstis (Linn.). 

 g^. Fifth caudal segment with compressed 



cariaate supero-lateral edges Subgenus Prionurus (Ehrb.). 



Type P. australis (Linn.). 



Hypothetical Pedigree of the Buthidse. 



FrionurM. 



Centrufus. 



leomttraides. 



Vroptectea. 



