376 Mr. R. I. Pococli on 



Centruroides exilicauda (Wood). 



Bufhus erilicauda, Vs'ood, Vioc. Ac. Pliilad. 18G3, p. 107; id. Journ. 



Ac. Philad. V. p. 360 (1863). 

 Centrums exilicauda, Mai-x, P. Ent. Soc. Wasli. p. 91 (1888). 

 Centruroides exilicauda, id. Proc. U.S. Mus. 1889, p. 211. 



$ . — Of about the same size and coloration as C sub- 

 yranosKS, Kr., being uniformly ochraceous with exception 

 of the eyes, which are black ; no distinct dorsal black bands, 

 merely an indication of a alightly paler median and lateral 

 spot on the terga ; a faintly defined dark band on lower side 

 of tail. 



Uppei'side of trunk and surfaces of tail noticeably more 

 coarsely and closely granular than in C. subyranosus ; the 

 last abdominal sternum closely granular throughout, the four 

 keels distinctly granular and closer to each other than in that 

 species, the fourth with traces of a pair of keels ; also short 

 lateral keels present on the terga. 



Tail longer and much thinner than in C. subyranosus, 

 about six times as long as carapace, as long as the third 

 segment of the tail, the latter twice as long as wide, fifth 

 segment about three times as long as wide ; vesicle smooth, 

 more globular, not granular, and with no subaculear tooth, 

 only the minutest trace discernible. (In C. subyranosus 

 the third caudal segment is distinctly less than twice as long 

 as wide and the fifth is only twice and a half as long as wide ; 

 the vesicle is granular.) 



ChelcB and leys more granular than in C. subyranosus, all 

 the crests on the hand stronger and more distinctly granular, 

 that of the underhand granular. Movable finger with 

 stronger lobe. Coxse of legs finely granular, especially along 

 their anterior edges. 



Pectinal teeth 19. 



Measurements in millimetres. — Total length 48 ; cara- 

 pace 4*5 ; tail 29, length of fifth segment 5*2, width 1*7, 



Loc. Lower California : San Jose del Cabo (in Mus. Brit.). 



The above-described specimen appears to belong to the 

 species from Lower California named Buthus exilicauda by 

 Wood, which was referred by Marx to the genus Centrurus, 

 and was subsequently made by this author the type of the 

 un characterized genus Centruroides and recorded from 

 St.Margaret^s Island. According to Wood, the species attains 

 a length of 45 millim. (20-21 lines), has 18 pectinal teeth, 

 very small hands, and no subaculear tooth. The colour is 

 said to be ''dilute aurantiaco-brunneus, interdura obscure 

 maculatus/' with generally an inferior stripe on the tail. 



