CLASSIFICATION 307 



The DIPLOCENTRINAE have a spur under the aculeus. They 

 form a small group of only eight species. The principal genus, 

 Diplocentrvis, is entirely Neotropical, but Nebo has a single Old 

 World representative in Syria. 



The URODACINAE, with the single genus Urodacus, are 

 Australian scorpions. As in the next sub-family, there are 

 rounded lobes on the tarsi, but there is only a single keel on the 

 " tail," and the lateral eyes are two in number. Six good and 

 three doubtful species are recognised. 



The SCOKPIONINAE are Asiatic and African forms, and are 

 recognised by the tarsi having a large lobe on each side, by the 

 convex upper surface of the "hand," by the presence of two 

 median keels on the " tail," and by the possession of three lateral 

 eyes. Palamnaeus (Heterometrus) has sixteen species in the 

 Indian region. There are about thirty species of Opisthoph- 

 thalmus, all natives of South Africa. Pandinus includes about ten 

 species, but there are only two species of the type genus Scorpio, 

 S. maurus and S. boehmei. 



The sub - family HEMISCORPIONINAE was formed for the 

 reception of the single Arabian species Hemiscorpion Upturns. 

 Its most striking characteristic is the cylindrical vesicle of the 

 tail in the male. 



The ISCHNURINAE differ from the Scorpioninae chiefly in the 

 absence of the tarsal lobes, the presence of a well-marked finger- 

 keel, and the generally more depressed form of the body and 

 hand. In the opinion of some authors they should be separated 

 from the Scorpionidae as a distinct family, the Ischnuridue. 

 There are more than twenty species, divided among six genera. 

 The type genus Ischnurus has only the single species /. ochropus. 

 There are eight species of Opisthacanthus, which has representa- 

 tives in Africa and America. 



Fam. 3. Chaerilidae. Sternum pentagonal with median 

 depression or " sulcus " rounded posteriorly. Two pedal spurs. 

 Stigmata circular. Two lateral eyes with a yellow spot behind 

 the second. Pectines very short. 



This small family has the single genus Chaerilus with but 

 seven species, natives of the Oriental region. 



Fam. 4. Chactidae. Two pedal spurs. Two lateral eyes 

 (or, rarely, no eyes) lout without yellow spot. Characteristic 

 dentition on movable finger of " hand" 



