KHOPALUKUS. 



37 



which the pecten rests (Tab. VIII. fig. 5 a). The pectines a little or very much wider in the basal than 

 in the distal half, and frequently there is a strong median lateral keel on the second and a weaker one 

 on the third caudal segment. 

 Type B. laticauda. 



Distribution. Cuba, Haiti, Central America, and the northern parts of South 

 America. 



Of the five species referred by me to this genus all differ from Centruroides in the 



thickness of the tail in the female, and its greater expansion in the male than in 



the former sex. Apart from this character, the structural features of the genus are 

 exemplified in the greatest perfection in the Brazilian species, R. borellii, sp. n., which 



possesses the median lateral keel on the second and third caudal segments, strongly 

 expanded pectines, and on the first abdominal sternum deep grooves which pass 

 inwards from the stigmata, and then turn abruptly forwards in a direction nearly 

 parallel with each other, enclosing a narrow, slightly raised area which ends on the 

 anterior border of the sternum in a blunt point. Two species, namely R. junceus 



(Herbst) and R. agamemnon (Koch), resemble R. borellii in the structure of the pectines 

 and the shape and depth of the sternal grooves, but have not acquired the median 

 lateral crests upon the second and third caudal segments ; whereas, on the other hand, 

 the remaining two species, R. laticauda and R. princeps, which possess the super- 

 numerary keel, have the pectines only a little broader basally than in Centruroides, and 

 the sternal grooves approaching those of that genus, being shallower than in the 

 remaining three species, and running obliquely forwards from the stigmata to meet in 

 an acute angle. R. borellii, in fact, occupies a central position, with R. junceus and 

 R. agamemnon approaching Centruroides on the one side and R. laticauda and 



R. princess on the other. 



Only one species of the genus has been recorded from Central America. 



1. RhopalimLS junceus. (Tab. VIII. figg. 5, 5 a, $ ; Tab. IX. figg. 1, 1 a, 6 .) 



Scorpio junceus , Herbst, Nat. ungefliigelt. Ins. iv. p. 65, t. 3. fig. 2 (1800) \ 

 Heteroctenus junceus, Pocock, Journ. Linn. Soc, Zool. xxiv. p. 392 (1893) 2 . 

 Centrums junceus, Kraepelin, Das Tierr., Scorpiones et Pedipalpi, p. 94 (1899) 3 . 



Mus 









Scorpio (Atreus) hemprichii, Gervais, Ins. Apt. iii. p. 54 (1844) 4 ; Arch. 



t. 11. fig. 18 (1844) 5 . 

 Scorpio hemprichii, Lucas, in Ramon de la Sagra's Hist. Nat. Cuba, Crust, et Ins. p. lxx, Atlas 



Anim. Artie, t. 5. figg. 5-5 c (1851) 6 ; Gervais, in Castelnau's Exped. dans TAmer. du Sud, 







Myri 



Miinch 







Wiss. Anst. viii. p. 135 (1891) 



. 









■ 



$ . Colour a tolerably uniform deep yellowish-brown ; the tail darker posteriorly, especially beneath ; fingers 

 black with yellow tips. Carapace coarsely granular, the granules subserially arranged at the sides. 











Terqa also coarsely granular, without trace of lateral keel. Sterna smooth, except quite at the sides ; 

 the' smooth depressed lateral area of the first smooth, the last finely granular, with four strong weakly 













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