OCR Text |
Show 122 MR. R. I. POCOCK ON THE SCORPIONS [Mar. 18, denticles are arranged in a long simple longitudinal series, which in the distal half divides into a number of oblique short rows ; the internal series consists of enlarged teeth set singly and at a distance from the series from which they arose: the external teeth of the external series are also arranged in a single row, the individual teeth being close to the median series and alternating with, but not forming a transverse line with, those of the internal series. The genus is further remarkable for the great size of the tail. Genus BUTHUS, Leach. Buthus (Leach), Thorell, Etudes Scorpiol. p. 8-type europceus (Linn.). This genus is unknown in America and Australia, but, including all the subgenera here admitted, is widely distributed elsewhere, being especially abundant in Africa and the Mediterranean district. Subgenus RHOPTRURUS, Karsch. (Plate XIII. figs. 1, 2, and Plate XIV. fig. 1.) Odonturus, Karsch, Sitz.Ges. nat. Fr. 1879, p. 119 (nom. praeocc). Rhoptrurus, id., Berl. ent. Zeits. xxx. p. 77 (1886). Babycurus, id. ibid. Hab. S. Africa, Madagascar. Movable digit of chelicerae with two teeth on the inferior border. In the digits of the chelae the posterior ends of the median rows of denticles are not enlarged, but are bent outwards, thus constituting the external series ; the internal series is formed by the enlarged and slightly separated anterior tooth of each median row. The cephalothorax is not keeled ; the tergites have one median keel. The tail is powerful or moderate, strongly keeled or almost without keels: there is a spine beneath the aculeus. The pectinal teeth are all alike. The sexes may differ in many ways, as in lsometrus ; thus the d of R. kirkii has a widened tail, a widened hand, aud a space between the base of the digits ; in R. baronii the pectines of the d are much larger than in the 2 • Of all the subgenera oi Buthus this one comes nearest to lsometrus, uniting lsometrus with Parabuthus. From lsometrus it may be distinguished by the dentition of the chelicerae, and from Parabuthus by the spine beneath the sting, the much less strongly dentate or granular tail, and by the arrangement of the denticles on the digits of the chelae. The genus Babycurus was separated from Rhoptrurus on the strength of the greater slenderness of the tail ; but since this is merely a sexual character belonging to the female, the "-euus cannot well be retained. This genus contains the following species:- R. dentatus, Karsch (under Odonturus), Sitz. Ges. nat. Fr Berlin, 1879, p. 119 ; Mombas. R. biittneri, id. (under Babycurus), Berl. ent. Zeits. xxx. p 78 pi. iii. fig. 1 (1886); Gaboon. l' ' R. centrurimorphus, id. ibid. fig. 2; Madagascar ; and the three species described below (pp. 137-141). |