Scorpions of the Genus Urodacus, Pet. 61 



time we know but a small fraction of tlie species of the genus 

 that actually exist. 



It may be added that Prof. Kraepelin, in his recent attempt 

 at a " Revision " of the Scorpions, makes a bold effort, 

 qualified by the liberal use of interrogation marks, to reduce 

 the species known at the time he was writing to two. I am 

 unable to find any justification for his opinion ; and since he 

 refrains from all mention of the localities whence the speci- 

 mens he examined were obtained, it is not possible even to 

 suggest whether one or more than one species were described 

 by him under the title U. novce-kottandice } Peters. 



The species that stand apart from the rest in their structural 

 features are the two from Arnhem Land. One of these, 

 namely U. Darwinii, has considerable claims to rank as a 

 distinct genus, as I at first considered it to be before the 

 species named planimanus came upon the scene. 



Urodacus Darwinii (Poc). 



Iodacus Dancinii, Pocock, Ann. & Mag. Nat. Hist. (6) viii. p. 245 



(1891). 



Loc. North Australia, Port Darwin in Arnhem Land 

 («/. J. Walker). 



This northern species, like U. excellens, occupies an isolated 

 position in the genus Urodacus. It is characterized by its 

 short and slender tail, by the absence of a median keel on the 

 dorsal surface of the flattened hand, &c. 



Urodacus planimanus, Poc. 



Urodacus planimanus, Poc. Ann. & Mag-. Nat. Hist. ((3) xii. p. '-V2\ 

 (1893). 



Loc. West Australia, 30 miles from Perth (H. W. J. 

 Turner). 



This species has the hands flattened as in U. DarwinUj 

 but in other respects more approaches U. novaz-hoUandice, 

 though easily to be distinguished from that species by its 

 narrow tail, deeply excised frontal border, &c. 



Prof. Kraepelin placed this species as doubtfully synony- 

 mous with U. Darwinii, supposing that it was perhaps based 

 upon a male example of a species of which U. Darwinii is 

 the female. Unfortunately for this view, the types of the 

 two species are females, and it may be added that, even if 

 they were of opposite sexes, there could be no justification 

 for the opinion that they are specifically identical. 



