CENTBUEOIDES. 



9^ 



00 



Centrums gracilis, Karsch, Mittheil. Miinch. ent. Ver. iii. p. 18 (1879) 3 ; Kraepelin, Jahrb. 



Hamb. Wiss. Anst. viii. p. 131 (1891) * ; Pocock, Journ. Linn. Soc, Zool. xxiv. pp. 385, 386 

 (1893) 5 ; Kraepelin, Das Tierr., Scorpiones et Pedipalpi, p. 92 (1899) 6 . 



Androctonus biaculeatus, Lucas, in Webb & Berthelot, Hist. Nat. Cauar., Aracbn. p. 45 (1835) 7 . 



Scorpio (Atraus) biaculeatus, Gervais, Ins. Apt. iii. p. 54, t. 23. fig. 1 (1844) 8 ; Arch. Mus. iii. 



p. 218 (1844) 



9 



My 



(18 



10 



Buthus biaculeatus, Wood, Journ. Acad. Nat. Sci. Philad. v. p. 366 (1863) u (part.). 

 Centrums biaculeatus, Thorell, Atti Soc. Ital. xix. p. 166 (1877) 12 . 



(1845) 



13 







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Tityus congener, C. Koch, loc. cit. p. 19, fig. 860 14 . 

 Tityus nebulosus, C. Koch, loc. cit. p. 25, fig, 862 15 . 



w 



Scorpio (Atreus) sayi, Girard, in Marcy's Rep. Red River, p. 269 (1853) ,5 . 



Scorpio {Atreus) nigrifrons, Berthold, Nachr. Ges. Gotting. 1846, p. 59 17 [teste Kraepelin). 



Centrums heterurus, Karsch, Mittheil. Miinch. ent. Ver. iii. p. 122 (1879) 18 . 



2 . Colour : carapace and terga deep reddish-black or brown, sterna paler but clouded with rich brown ; tail 

 yellowish-brown, paler than the terga, darker posteriorly and beneath ; legs ochre-yellow ; chelae rather 

 darker than the legs, the hand redder than the brachium, fingers nearly black with yellow tips ; chelicerse 

 deep brown ; coxse, sternum, &c. pale. Upperside of trunk studded with coarse, shining, symmetrically 

 arranged tubercles, an area extending obliquely forwards on each side of the median eyes and the 

 interstices between the rows of coarse tubercles finely granular ; anterior portion of terga finely and 

 closely granular ; carapace as long as the second caudal segment, a little shorter than the third 

 or fourth, as long as brachium, rather longer than humerus. Tail about six and a half times as long 

 as carapace, all the crests evenly granular, the interspaces at most very weakly granular ; vesicle weakly 

 granular below, slightly wider than high; subaculear spine well developed, triangular, its upper 

 (anterior) edge lightly convex, the distance between it and the base of the aculeus exceeding the width of 

 the base of the spine. Sterna shining, the second, third, and fourth coarsely punctured in the middle, the 

 last very finely granular laterally, and furnished with four keels, the medians nearly smooth, anteriorly 

 abbreviated, the laterals converging inwards posteriorly against the medians. Chelce shagreened, 

 the crests on humerus and brachium closely granular ; hand with one complete weakly granular finger- 

 keel, an incomplete keel close to it on the outer side ; width of hand about one-third the length of the 

 movable finger, and about two-thirds that of the underhand, which is almost half the length of the 

 movable finger ; the latter lobate at base, the immovable finger with corresponding shallow excavation, 

 the movable with nine rows of teeth. Pectinal teeth 25-30. 



cJ . Smaller and slenderer than female. Tail much longer, about eight times as long as the carapace, which 

 is scareely as long as the first segment, and about three-quarters the length of the second ; vesicle with 

 nearly straight sides and shouldered at base of vesicle on each side, its posterior surface much less convex. 

 Chelce a little longer than in female, the carapace a little shorter than the humerus. Pectinal 

 teeth 30-36. 



Measurements in mm. — 5 • Total length 102, carapace 9*5; tail 62, caudal segments 1 + 2 (second 9*5) 18-5, 

 fifth 12. (S . Total length 118, carapace 9*5; tail 78, caudal segments 1 + 2 (second 12*5) 24, 

 fifth 15. 



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Bab. Mexico, Lake of Chalco, Yucatan (coll. Keyserling, in Mus. Brit.\ Atoyac in 

 Vera Cruz, Teapa in Tabasco (H. H. Smith), Temax in N. Yucatan (Gaunter) ; British 



Honduras (In do-Colonial Exhib.), Stain Creek (Robertson) ; Guatemala, Panzos 

 (Conradt), Salinas de Nueve Cerros, Rio Negro (Sarg). — Venezuela, Caracas; 

 Antilles, Cuba, Jamaica. 



jbiol. centr.-amer., Arachn. Scorp., October 1902. 













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