398 ME. E. I. POCOCK OS THE 



21. Opisthacatstthtts elatus (Gervais). 



? Scorpio leptums, Pal. de Beauvois, Insect es etc. p. 191, Apt. pi. v. 

 fig. 4. 



Scorpio elatus, Gervais, Arch. Mus. iv. p. 235, pi. xii. figs. 46-49 ; id. 

 Ins. Apt. p. 69. 



Opisthacanthus Kinbergii, Thorell, op. cit. p. 172. 



Carapace somewhat flat, wider than long; granular througliout ; 

 median eyes large, scarcely elevated on a tuhercle ; lateral eyes 

 very prominent, the distance between the anterior and median 

 twice as great as between the median and posterior, which are 

 subcontiguous, 



Tergites granular and rugose, the last not carinate, but 

 furnished posteriorly with two small tubercles. 



Sterna smooth, the last subcostate. 



Tail 2h times the length of the carapace, which is as long as 

 the first two segments and more than half the third, narrowed 

 posteriorly ; the segments mesially excavated above, with rounded 

 smooth edges, subcarinate beneath but granular only posteriorly ; 

 vesicle smooth, with long hairs beneath the aculeus. 



Falpus: humerus denticulate in front aud behind, the upper 

 surface smooth distally ; hracJiium with a strong denticulated 

 crest at the proximal end of its anterior surface ; mantis coarsely 

 granular above, rugose beneath, denticulate in front ; the " hand- 

 back " about as long as the movable digit, the width of the 

 hand about f the length of the "hand-back "; the digits scarcely 

 sinuate, and lobate at the base. 



Legs with femora granular beneath. 



Genital operculum heart-shaped, pointed posteriorly, nearly as 

 long as wide, without trace of suture. 



Pectines very small, only a little longer than the width of the 

 operculum, furnished with 7 teeth. 



S . Tail a little more than three times the length of the 

 carapace. Digits correspondingly lobate and sinuate. Genital 

 operculum rounded, and not pointed behind. Pectines much 

 larger, and furnished with 12 teeth. 



Measurements in millims. of adult male. — Total length 

 87, of carapace 13, of tail 41, of "hand-back " 15, width of 

 hand 11. 



Locality. Hayti, according to specimens in the British Museum. 



It also occurs in Colombia. 



