ON SOME OLD-WOULD SCORPIONS. 433 



On some Old-World Species of Scorpions belonging to the Genus 

 Isometrus. By E. I. PococK, of the British Museum (Nat. 

 Hist.). (Communicated by W. Pebct Sladen, F.L.S.) 



[Bead 1st May, 1890.] 



(Plate XI.) 



The examination of the Buthidee contained in the collection of 

 the British Museum has brought to light a number of new species 

 of the group. Those referable to the genus Isometrus are described 

 in the present paper, which contains in addition a few remarks 

 upon the synonymy and affinities of one or two previously known 

 forms. 



Speaking genevdiWY, Isometrus may be described as almost cosmo- 

 politan, although representatives have not yet been recorded from 

 the Palsearctic Region. However, in Central and South America, 

 in Africa south of Sahara, in India, Indo-Malaya, Austro-Malaya, 

 and Austi'alia the species are fairly abundant, and the number at 

 present known will no doubt be largely added to in years to come. 



In the Old World the species may nearly always be recognized 

 from others of the family by the variegated black and yellow 

 pattern of the upper surface of the body and legs ; in some 

 instances, however, the limbs andtruuk are concolorous or nearly 

 so. The colours, allowing for variations, are of some use in the 

 recognition of the species ; but the best characters for this pur- 

 pose are to be obtained from the form of the tail, the keels on the 

 tail and trunk, the width of the hand, length of fingers, &c. 



The sexes differ largely and in a variety of ways. The male 

 may almost certainly be detected by possessing some one or more 

 of the following features : — The hand will either be longer and 

 relatively more slender, or stouter than it is in the female ; at the 

 base of the dactyli there is often a wide space formed by the 

 sinuation of the proximal half of these organs ; the trunk is more 

 slender ; the tail much or a little longer, and sometimes only 

 thicker. 



On IsOMETEUS TEICAKINATUS, Simoii. (PI. XL figs. 1-1 d.) 

 {Simon, Ann. Mus. Genov. xx. p. 47, 1884.) 



Pondicherry, Madras. 



The British Museum possesses three specimens of a species of 

 Isometrus sent by Mr. Jerdan from Madras, which are unques- 



LINN. JOTJRN.— ZOOLOGY, VOL. XXIII. 31 



