514 Mr. R. I. Pocock on new Species of 



exceedingly well-marked one, the characters of which may 

 be seen from the subjoined table. 



Tityus androcottoides (Karscli). 



Isometrus androcottoides, Karsch, Mittli. Miinch. ent. Ver. 1879, 

 p. 114. 



Karsch gives no locality for this species, which he regarded 

 merely as a variety of americanus. The British Museum, 

 however, has half a dozen examples obtained in Demerara 

 (British Guiana) by Messrs. Sclater, Turner, and Bower. 



Specimens from Trinidad which were- formerly referred by 

 me to this species may be recognized from the Demerara 

 forms by the characters mentioned in the synopsis given 

 below, the characters being constant in the sixteen examples 

 that I have seen. 



Tityus trinitatisj sp. n. 



Isometrus androcottoides (Karsch), Pocock, Ann. & Mag. Nat. Hist. 



1889, iv. p. 57. 

 Tityus androcottoides, Pocock, Journ. Linn. Soc, Zool. xxiv. p. 377 



(1894) (in part). 



Differing from the closely related Guiana form, which 

 agrees with Karsch's description of androcottoides, in having 

 the two inferior keels on the second caudal segment distinct, 

 those on the third united on the posterior third of the seg- 

 ment, and those on the fourth in tlie posterior two thirds of 

 the segment. In Demerara specimens which I refer to andro- 

 cottoides the lower keels are united on the posterior third of 

 the second and on the posterior two thirds of the third. 



Pectinal teeth lG-17. 



Loo. Trinidad {J. E. Broadway and J. II. Hart) . 



The characters of all the Trinidad specimens that I have 

 seen are very constant in young and adults of both sexes. 



Tityus magnimanus, sp. n. (Figs. 4, 4 a.) 



6 . Colour a reddish brown, the fourth and fifth caudal 

 segments, the vesicle, and digits blackisli. 



Tail barely six times the lengtli of the carapace, whicli 

 equals the length of its third segment, nearly parallcl-sided, 

 the third and fourth segments being only sliglitly wider than 

 the first; the inferior keels complete on the second segment, 

 but represented by a single median one on the posterior third 

 of the third and on the posterior two thirds of the fourtli ; the 

 intercarinal spaces almost smooth, scarcely perceptibly gran- 

 ular ; the posterior graimle of the upper crests of segments 2 to 



