Mr. R. I. Pocock on Neotropical Scorpions. 89 
inferior lateral keels present too on all the segments, and finely 
granular at least on the fourth; the inferior median keels 
entirely obsolete on the first, just appearing on the second, 
still stronger on the third, plainly visible and granular on the 
fourth, this segment consequently having eight distinct 
granular keels; the fifth segment flat above behind, granular 
at the sides, with squared granular edges; lateral surface also 
granular, with indistinct median lateral keel, the lower surface 
with three inferior granular keels, and the intervening spaces 
also serially granular; vestcle moderately large, wider than 
the fifth segment, and almost as wide as the second; its 
height is about equal to the width of the fifth; thickly 
granular beneath, smooth above; aculeus more than half the 
length of the vesicle. 
Palpi elongate ; the humerus granular above, the brachium 
granular above, smoother behind, with a conspicuous bifid 
denticle above at the base of the anterior surface; manus 
rather narrow, not twice the width of the brachium, indis- 
tinctly keeled above and marked with very short series of 
minute granules; the length of the hand-back much greater 
than the width of the hand, the digits long, the basal tooth on 
the immovable digit scarcely larger than the rest. 
Legs nearly smooth, the femora of the last pair only very 
weakly granular. 
Pectines short, with 6-7 teeth. 
Measurements in millimetres.—Total length 53, length of 
carapace 8°5, of tail 27, of fifth segment 7°5, width 2°2; width 
of vesicle 2°8 ; width of brachium 2°7, of hand 4°5; length of 
hand-back 7, of movable digit 8. 
Two female specimens from Venezuela. 
Chactas chrysopus, sp. n. 
Colour piceo-ferruginous ; legs flavous. 
Carapace as long as the anterior three caudal segments, 
very smooth, very minutely granular at the sides; the front 
border with a shallow emargination; the median eyes large, 
the distance between them about equal to a diameter; the 
anterior lateral eye large and very prominent; the posterior 
smaller and separated from it by a distance about equal to its 
own diameter. 
Tergites entirely smooth, the last only very minutely 
granular at the sides, with two tubercles on each side. 
Sterna entirely smooth and polished. 
Tail about three and a half times the length of the cara- 
pace, the third segment as long as wide, the first and second 
