88 Mr. R. J. Pocock on Neotropical Scorpions. 
more than half the length of the hand-back, which itself 
equals the length of the movable digit ; the manus convex 
above, not keeled, granular internally and minutely reticulato- 
granulate above ; the digits not dentate. 
Legs almost entirely smooth ; the lower edge of the femora 
granular. 
Pectines short, with 7 teeth. 
Measurements in millimetres.—Total length 53, of carapace 
75, of tail 27; width of first segment 3:4, of fifth 2°5; 
width of brachium 2°5, of hand 4; length of hand-back and 
of movable digit 7. 
Loc. Colombia. Two female examples, one collected by 
M. Goudot, the other from the collection of the late Count 
Keyserling, in honour of whom I name the species. 
‘This species is nearly related both to Ch. Van Benedenit, 
Gervais, and to Ch. lepturus of Thorell. From the former it 
may be recognized at once by having the superior caudal 
keels evident and denticulate, and by having the humerus, 
brachium, and manus and last tergite granular; moreover, in 
the female of Van Benedenii the tail is longer and the palpi 
are more robust, the width of the hand as compared with the 
length of the hand-back being as 5: 7:3, 
From the Museum example that I identify as lepturus, 
Thorell, Aeyserlingti may be recognized by having the hand 
unkeeled, the palpi and last tergite more granular, the upper 
surface of the tail more deeply excavated and more granular, 
and the superior and supero-lateral keels better developed 
and more granular. 
Chactas Simonit, sp. n. 
Colour piceo-ferruginous, legs paler. 
Carapace smooth on the summit of the prominences, granu- 
lar over the rest of its surface, nearly as long as the anterior 
three caudal segments 3 the median eyes of average size, sepa- 
rated by a space that is rather greater than a diameter; the 
distance between the lateral eyes about equal to a diameter ; 
the anterior lateral eye prominent. 
Tergites smooth, the last finely granular, with two 
tubercles on each side. 
Sternites smooth and polished. 
Tail less than three and a half times the length of the 
carapace, narrowed posteriorly, the second segment as long as 
wide, the upper surface of the segments nearly flat and 
smooth, the superior and supero-lateral keels developed and 
granular, the former with enlarged terminal granule; the 
