:376 ME. E. I. POCOCK ON THE 



Genus Isometeus {Semp. Sf EJirb.). 



1. Isometeus maculattis (Be Geer). 



This small and slender Scorpion, which is widely distributed 

 througliout the tropical and subtropical countries of tbe Old 

 and New Worlds, is perhaps the best known species of the 

 Order. 



The British Museum has examples from the following West- 

 Indian Islands : — St. Domingo ; Jamaica ; St. Thomas ; St. Croix 

 {A. Newton) ; Barbados (S. W. Feilden) ; Union Island, 

 Grrenada (S. H. Smith); and Trinidad {W. E. Broadway). 



Genus Tittus, C. Koch. 



Tityus, C. Koch, Die Arachn. iii. p. 33 (1836). 



Isometrus, Thorell, Etudes Scorpiol. p. 83 (1876) ; Karsch, Mitth. 

 Munch, ent. Ver. p. 18 (1879); Pocock, Free. Zool. Sac. 1890, 

 p. 119. 



Phassus, Thorell, ibid. ; Kraepelin, Jahrb. Hamb. Wissen. Anst. p. 17 

 (1891). 



Androcottus, Karsch, op. cit. p. 11. 



This genus was estabhshed by C. Koch in 1836 upon Scorpio 

 I iahiensis of Perty. This species is clearly therefore the type of 

 the genus, and if such species as hahiensis and its allies be 

 considered generically distinct from Isometrus maculattis, the 

 name Tityus must be retained' for them. As I have elsewhere 

 pointed out, I cannot see that Dr. Thorell was justified in 

 selecting the South-African species lineatus as the type of 

 Tityus, especially as Peters, who was the first to give an intel- 

 ligible revision of the Scorpions, had previously characterized 

 these South- African forms as his genus Uroplectes. 



In my revision of the genera of the Buthidce, published in the 

 Proc. Zool. Soc. 1890, pp. 114-127, I followed Dr. Thorell and 

 Karsch in considering the species of the hahiensis group as 

 congeneric with the maculatus group. Prof. Kraepelin, however, 

 has subsequently, and I think rightly, separated the former as a 

 distinct genus, for which he selected Thorell's name Phassus. 

 Tityus, however, has the priority, and I have consequently 

 restored this old genus of Koch's. 



