124 Mu. R. I. I'ocoCK ON TUK SCORPIONS [Mar. 18, 



Subgenus Parabuthus, nov. 



PrioHurus, Elirenberg (iu part); Karsch (in part). 



Tyjje, P. iiosoma (Ehrb.), Symb. Phys. no. 10, |)1. ii. tig. d. 



Hab. Ethiopian Region. 



Ehrenberg included in his group Prionurus a species named liusoma 

 which departs sufficiently widely from the type P. funestus to be 

 worthy of special recognition. Dr. Karsch was the first to point 

 out this fact ; but iu attempting to establish a separate geuus of 

 which Iiosoma was to be the type, this author ap])ears to me to have 

 fallen into error in two particulars. In the first place, since Thorell 

 had restricted Androcionus to those Scorpions which were termed 

 Prionurus by Ebrenberg — a proceeding justifiable on the grounds 

 that no type had been named for Androctonus and that a genus 

 must supersede its subgenus — it is clear that the type of Prionurus, 

 \\a.me\y funestus, is also the type of Androctonus and that Prionurus 

 must, in that case, be regarded as a synonym oi Androctonus. But 

 Dr. Karsch, wishing to preserve the term Prionurus, selected as the 

 type Ehrenberg's species Iiosoma, on the understanding that Iiosoma 

 is geuerically, or at all events subgeuerically, distinct from funestus. 

 But, as stated above, it seems to me to be absolutely essential to 

 select as the type of a genus the species which is the first referred 

 to it by the author — unless any other be specially mentioned by him 

 as typical — and never to transfer this generic term from this species 

 and its allies to another, which differs from the type in generic 

 characters, although this other was referred originally to the same 

 genus. Consequently I hold \ha.t funestus is the type of Prionurus, 

 and that the transference of the name to Iiosoma can only lead to 

 confusion. 



I have therefore found it necessary to create a new subgeneric 

 name for Iiosoma and its allies, since the group appears to me to be 

 a perfectly natural one, agreeing both in important characters and in 

 geographical distribution. 



But the group as characteiized by Dr. Karsch cannot stand, 

 inasmuch as it was based upon a character — the presence of a median 

 lateral keel on the fourth caudal segment — which may or may not 

 e.xist within the limits of a single species, and is valueless for generic 

 distinction. Moreover, as thus defined the genus is quite an un- 

 natural group, inasmuch as it includes forms, such as e. g. lioso/jia and 

 petopporiensis (^gibbosus), which are widely separated from each other, 

 and in addition conipletely severs pelopponensis from its nearest 

 allies — europceus, leptocheles, &c. 



The subgenus may be characterized thus : — 

 On the digits of the clielae the external series of teeth are formed 

 by the enlargement and partial assumption of a lateral position of 

 the two posterior teeth of the median rows ; the internal series by 

 the enlargement and separation of the anterior tooth of each median 

 row. Tlie cephalot borax is not costate, and the tergites are 

 furnished with only a median keel. The tail is powerful and strongly 

 keeled, but there is a marked tendency to obliteration on tlie part of 



