ABTHEOPOD FAUNA OP THE WEST INDIES. 391 



mediate in character between Thorell's nif id us •dnd his tenuis: 

 consequently I do not hesitate to adopt the above synonymy, 

 which Prof. Kraepelin was the first to establish. 



This species agrees tolerably clot^ely in most of its characters 

 with C. testaceus and C. insulaaus ; it may, however, be at once 

 recognized by its thicker hands and relatively shorter fingers. 



15. *Centrueus peinceps, Xarscli, op. cit. p. 121 ; Kraepelin, 

 op. cit. p. 139. 



Locality. Port au Prince (Hayti). 



This species is very likely referable to the following genus, 

 Heteroctenus, to both of the known species of which it offers a 

 gre »t likeness. 



It may be recognized from all the other known West-Indian 

 species of Centrums in having the median lateral keel complete 

 on the 2ud and 3rd segments. 



The following two are of doubtful position both generically 

 and specifically : — 



*TiTTUS GBisEFS, C. Koch, Die Arachiiden, xi. pp. 43-45. 



This species, described from St. Tliomas, may be either a 

 Centrums or a true Tityus. There is no apparent reason for 

 supposing that it is Scorpio griseus of Tabricius. 



*ScORPio GRISEUS, Fair. Ent. Syst. ii. p. 435, no. 7. 



" S. pectinibus vigintiquinque dentatis, mauibus subcilia'.is 

 ovatis. 



" Habitat in Americse Insulis. 



" Corpus parvum, pallide testaceum, immacnlatum. Manus 

 subciliatae, chelis ovatis, digitis f uscis. Cauda corporis longitu- 

 dine, 6-articulata, ungue acutissimo." 



Heteeoctenijs, gen. nov. 

 (erepos, diff'erent ; (creJs, Kreros, a COmb.) 



Kesembles Centmrus (Ehrb.) in most respects. 



Pectines, in both sexes, expanded at their proximal extremity 

 owing to an increase in width of the intermediate lamellae of 

 the basal half of the organ. The sternal plate that supports the 

 pectines large, with ovate posterior border. The following 

 sternum that bears the first pair of stigmata marked on each 

 side with a strong groove which rises from the inner end of the 



