520 Mr. R. I. Pocock on new Species of Scorpions. 



once recognized by having the abdominal sterna thickly 

 granular and densely variegated, not to mention the iufusca- 

 tion of the cox^ and the presence of two crests on the fourth 

 sternite. These two characters, in fact, coupled with the 

 absence of the pectinal lobe, indicate a close relationship be- 

 tween T. atriventer and a group of species coratnon in South 

 America, of which 2\ columhianus^ Thor., is a well-known 

 example. 



Some of the differential characters of this group of species 

 are set forth in the accompanying table : — 



a. Upper keels of second, third, and fourth caudal 



segments posteriorly elevated and ending in 

 a strong' triangular tooth, 

 a^ Vesicular tooth small, spiniform ; tail 



coarsely granular columhianus, Thor. 



(New Granada.) 

 b^. Vesicular tooth deep and blade-like ; tail 



much more linely granular Quelchii, Poc. (Deme- 



rara.) 



b. Upper keels of segments 2-4 not or hardly 



elevated posteriorly, at most ending in an 

 enlarged granule. 

 a^. Vesicular tooth small and spiniform; tail 



obsoletely granular atriventer, sp. n. Gre- 

 nada (W. Indies.) 

 b"^. Vesicular tooth deep .and blade-like ; tail 

 and its keels more distinctly granular. 

 a'. Vesicle and fifth caudal segment pale, not 

 deeper in colour than the rest of the tail ; 

 hand in male only as wide as the bra- 

 chium, digits not sinuate ; fifth caudal 



segment not elevated pusiUus, Poc. (Igua- 



rassu.) 



fc'. At least the vesicle much darker than the 



rest of the tail : hands expanded, fingers 



sinuate, and hfth caudal segment elevated 



in male. 



a*. Vesicular tooth very deep, obliquely 



truncate at the tip ; coxa of cepnalo- 



thorax strongly infuscate stilvestris, Poc. (San- 



tarem.) 

 fc*. Vesicular tooth less deep, more pointed 

 apically ; coxae of cephalothorax 



scarcely at all infuscate jiaraguayeyisis, Kraep. 



(Paraguay.) 



Tityus rufofiiscuSj sp. n. 



Colour a uniform brownish black, like that of T. pachyurus. 

 Carapace with anterior border transverse, scarcely percep- 

 tibly emarginate ; terya with tjie median longitudinal and 



