316 ON SCORPIONS COLLECTED AT ADEN. 



Plate IX. (conthmed). 



Figs. 6 a, 6 b. Parabuthus villosus (Peters). Upper and lateral views of tail of 

 2 example from Benguela (W. Africa), in which the carapace 

 measures 12 mm. — These figures are inserted to convince those 

 authors, who persist in citing villosus as a synonym of liosoma, 

 that the two are perfectly distinct. Compare the large vesicle, 

 stout and curiously curved aculeus, the elevated 5th segment, 

 and the straighter, more parallel-sided, more thickly hairy tail. 



Addendum. 



List of the Scorpions ohtained hy Colonel Yerhury at Aden 

 in the Spring q/1895. 



1. Hemiscorpius lepturus, Pet. Aden (many specimens). 



2. Nebo flavipes. Sim. Aden, Haithalhim, Shaikh Othman. 



3. Parabuthus liosoma (Hempr. & Ehrenb.). Aden, Haithalhim, Lahej, 



Shaikh Othman. 



4. Buthus dimidiatus, Sim. Aden, Lahej, Shaikh Othman. 



5. Buthus acute-carinatus, Sim. Aden, Lahej, Haithalhim. 



6. Butheolus thalassinus, Sim. Aden, Lahej, Haithalhim, Shaikh Othman. 



This little collection came to hand whilst this paper was passing through the 

 press. The most interesting species of the lot are the first and last of the list- 

 Hemiscorpius lepturus seems to be represented by very few specimens in the 

 collections of Europe. Up to the present time, so far as I am aware, the 

 British Museum and the Museum at Berlin are the only institutions which 

 possess it. The British Museum received it for the first time some two years 

 ago, when Mr. Gates sent home one specimen from Aden. Yet, judging from 

 Col. Yerbury's collection, the species is not uncommon in Aden ; and it evidently 

 has a wide range, since it extends at least as far to the north as Baghdad, 

 Butheohts thalassinus is new to the British Museum ; and the acquisition of 

 seven specimens has filled vip an important gap in our series of Scorpions, 

 Moreover, it has enabled me to compare the species both with BtUhus Benti and 

 with Nanobuthus Andersoni. The latter differs from Butheolus in having the 

 anteocular area of the carapace almost horizontal, the lower border of the im- 

 movable mandibular digit unarmed, in the partial degeneration, both in number 

 and size, of the median rows of teeth on the digits of the chela and the corre- 

 sponding increase in strength of the lateral teeth. According to Simon's 

 description of B. thalassinus, the tail is posteriorly dilated, and there is only 

 one inferior tooth on the immovable mandibular digit. The 3rd and 4th 

 segments of the tail, however, are scarcely wider than the 1st, and sometimes 

 at least there are two teeth in the position mentioned above. In both these 

 respects the species approaches B. Benti ; but the two are und oubtedly specifically 

 distinct. 



