Scorpions of the Genus Heterometrus. 365 



smoothness of the inferior keels on the last abdominal and first 

 caudal segments, the spine- armature of the tarsi, &c. 



The known species may be tabulated as follows : — 



a. Keels of last abdominal sternum and of uuderside of 



first caudal segment smooth ( 2 ) Boehmi. 



b. Keels of last abdominal sternum and of underside of 



first caudal segment coarsely granular {<$ $). 



a 1 . Genital operculum divided ; terga and sterna finely 



granular or shagreened ( 3 ) . 



a 2 . Hand in adult wider than length of carapace, 



distinctly crested above ; immovable finger short, 



triangular ; a crest on underside of brachium 



behind; tail thick, fifth segment less than 



twice as long as wide, third as wide as or wider 



than long maurus. 



b 2 . Hand narrower than length of carapace, not 

 visibly crested above ; immovable finger long ; 

 no crest on underside of brachium ; tail narrow, 



third caudal segment longer than wide palmatus. 



b l . Genital operculum undivided ; terga and sterna not 

 shagreened ( 2 )• 

 a 3 . Third and fourth caudal segments with inferior 

 keels strong and granular. 

 «'. Median eyes small, vesicle not inflated. 



a 5 . Genital operculum much wider than long, 

 transversely elliptical; lower side of bra- 

 chium with distinct smooth crest behind ; 

 hand more strongly granular and keeled, &c. maurus. 

 b s . Genital operculum heart-shaped, as long or 

 nearly as long as wide ; lower side of bra- 

 chium evenly rounded behind ; hand less 



coarsely granular and crested fuscus. 



6*. Median eyes large ; vesicle expanded propinquus, 



I 3 . Inferior keels of third and fourth caudal segments 

 smooth, only uneven with setal pores ; median 

 eyes large. 

 rt°. Hand with a pair of strong smooth finger-keels, 

 and ornamented above with a distinct net- 

 work of smooth ridges arabicus. 



b 6 . Hand almost smooth above, scarcely visibly 



sculptured ; its crests obsolete Townsendi. 



N.B. — Attention must be drawn to the omission from the 

 ' Tierreich ' of the following names which have been applied 

 to various forms of the genus Heterometrus : flavus, rufus, 

 fuscus, and minor. Apart from the possibility that these 

 forms may in future take rank as distinct species, the re- 

 cording of such names is necessary to prevent their applica- 

 tion to new species by students who have no opportunity of 

 consulting all the literature of the subject and look to a work 

 of the aspirations of the ' Tierreich ' to supply at least a 

 complete list of the names that have been employed in each 

 genus. 



