516 Mr. R. I. Pocock on new Species of 



Though belonging to the T. androcottoides section, as shown 

 by the fusion of the inferior caudal keels, this species 

 differs from both androcottoides and trimtatis in having the 

 tail, sterna, and coxje much smoother. The sexual characters 

 also are strikingly different, the carapace in the male of the 

 last-mentioned being much shorter than the third caudal 

 segment and less than one seventh the length of the whole 

 tail. The chelse, moreover, are slender, the width of the 

 brachium being less than one third of its length, the hand 

 narrow, digits contiguous, &c. 



Synoptical Table of the previously discussed Species of the 

 americanus Group 0/ Tityus. 



Males. 



a. Two inferior caudal keek on segments 2 to 4 

 distinct, 

 a'. Vesicle without granules below, punctured ; 

 hand-back excelling carapace in length ; 

 (tail moderately robust, with strongly den- 

 ticulate upper edges; chelae long ; brachium 

 narrower than vesicle, much narrower 



than hand ; 15-17 pectinal teeth) macrochirus, sp. n. 



b^. Vesicle granular below ; hand-back less 

 than length of carapace. 

 a^. Vesicle much wider than width of bra- 

 chium, its width nearly equal to the 

 length of the first caudal segment and 

 equal to the space between the anterior 

 edge of the ocular tubercle and the pos- 

 terior border of the carapace ; the tooth 

 close to the base of the aculeus; 15 



pectinal teeth forcipula, Gerv. 



J'. Vesicle naiTower, its width much less 

 than the length of the first caudal seg- 

 ment and less than half the length of 

 the carapace ; tooth further from the 

 base of the aculeus. 

 c'. Tail strongly incrassate posteriorly, 

 width of the fourth segment exceed- 

 ing half its length ; hand large, much 

 wider than brachium, its width ex- 

 ceeding half the length of the hand- 

 back, digits strongly sinuate and 

 lobate. 

 a*. Tail very stout posteriorly, the width 

 of the fifth segment equal to the 

 length of the second and just equal 

 to the median length of the cara- 

 pace ; hand also much wider, ^Hth 



digits more strongly sinuate pachyuriis, sp. n. 



b*. Tail less stout ; the width of the 

 fifth segment considerably less than 



