91 



and aculeus 5.5, of aculeus 1.8; length of humerus 4, of brachium 

 4.3; of manus and dactyli 9.5, of morable dactylus 5.4, of hank-back 

 4.5; width of hand 5.5, of brachium 2.7, of humerus 2.2; sternum, 

 length from posterior angle to middle of anterior border 2.2, width 

 across posterior angles 2, width in front 1.6. 



In the smallest specimen, which is also paler in colour, the manus 

 is narrower, its width not equalling the length of the movable dacty- 

 lus (3: 3.5). 



I suspect that Thorell's genus Chelomachus ') is not distinct from 

 Chaerilus. It was established on the grounds that the sternum is as 

 wide as long and not longer than wide as in Chaerilus. But in these 

 specimens of variegatus the length of this plate only exceeds the width by 

 the merest fraction. Indeed if the length be taken along the middle line 

 it is only equal to the width across the posterior angles. In this genus 

 the sternum approaches the triangular form that is seen in the Buthidae ; 

 and another curious point in which this species at least resembles 

 this family is the presence of that remarkable smooth > shaped area 

 on the tergites which is so common in many species of Buthidae. 



In addition to Chelomachus , I suspect that my genus Uromachus will 

 also have to fall as synonymous with Chaerilus. This genus was based 

 upon specimens exactly agreeing with Chaerilus except in the strange 

 shape of the caudal vesicle. But since this peculiarity was not correlated 

 with other structural features, I thought that it might prove to be 

 sexual. And at the time, I did not recollect that Peter's genus Hemis- 

 corpio presents much the same modification of this segment ; and since 

 the two genera belong certainly to distinct sub-families and there is no 

 direct affinity between them, it struck me that the probability that 

 this character would prove to be sexual was sensibly increased. There 

 is, however, so far as I know, no direct evidence of the fact. 



6. Chaerilus cavernicola , sp. n. (PL VI, fig. 5 — 5a). 



. Three specimens 2 adult (?cf and Q), and 1 young (?cf) from the 



cavern Ngalau near Pajacombo in Sumatra. 



Colour fuscous, variegated with flavous, intercarinal spaces of the 

 tail mostly flavous, keels on tail and hands fuscous with flavous 

 spots, dactyli fuscous, fulvous at the apex, under surface of trunk 

 ochraceous, of hands rufo-ochraceous. 



1) Ann. Mus. Geu. XXVII, pp. 583—584. 



