82 Mr. E. L Pocock on Neotropical Scorpions. 



prominent. The ocular tubercle prolonged in front almost as 

 far as tlie anterior emargination ; the anteocular area there- 

 fore is not mesially grooved. 



This genus resembles Chactas, except that in Chactas the 

 ocular tubercle is short and terminates in front in a point 

 from which a deep groove runs forwards to the (usually) 

 shallow emargination of the anterior border ; the anterior 

 lateral eyes too are generally very prominent. It also very 

 closely resembles TeutJirmistes, of which the British Museum 

 has several examples, referred to atramentari'us, from Ecuador ; 

 but in this last genus the anteocular region of the carapace 

 is much more strongly sloped downwards and forwards and 

 the anterior border is not or scarcely emarginate. 



Heterochactas Gervaisii, sp. n. 



Colour piceous, with ferruginous legs and vesicle and 

 redder feet. 



Caraj)ace nearly as long as the first three caudal segments, 

 nearly smooth above, somewhat thickly granular at the sides, 

 the median sulcus not continued in front of the ocular tubercle ; 

 the anterior border somewhat deeply emarginate in the middle, 

 rounded at the sides ; the anterior lateral eye not prominent ; 

 median eyes small, separated by a distance about equal to 

 three diameters. 



Tergites nearly smooth, at most obsoletely granular, the 

 last finely and closely granular, with two tubercles on each 

 side. 



Sternites smooth and polished. 



2 ail about three and a half times as long as the carapace ; 

 the anterior four segments smooth beneath and not keeled, 

 marked with a few coarse punctures ; the upper surface 

 scarcely excavated and very feebly granular, the fourth and 

 fifth segments entirely flat, the superior and supero-lateral 

 keels present and finely granular, as also are the spaces between 

 them ; the tail narrowed posteriorly, the second segment a 

 little wider than long, the third a little longer than wide, the 

 fifth more than twice as wide as long, finely granular above, 

 flat in its posterior two thirds, its edges squared and granular, 

 its sides and lower surface also finely granular, with a poste- 

 riorly abbreviated weak median lateral keel and granular 

 anteriorly weak inferior keels ; vesicle large, higher and con- 

 siderably wider than the fifth segment, granular below and at 

 the sides, flat and sulcate above ; vesicle short. 



Palpi robust, not large; humerus granular above and in 

 front and carinate ; hrachium not denticulate nor granular, 



