Thelyphonidse in the British Museum. 133 



Thelyphonus proboscideus, Butler, Ann. & Mag. Nat. Hist., Sept. 1872, 



p. 203, pi. xiii. fig. 3, rf . 

 Thelyphonus parvimanus, id. Cist. Ent. i. p. 130, fig. 3 (1873), $. 



This genus is nearly allied to Hypoctonus, Thorell, of 

 which formosus, Butler, is the type — a genus which, according 

 to Mr. Oates, is represented by several species in Burma. 

 But, apart from the presence of the above-mentioned spine 

 upon the coxal apophysis of the chela, Labochirus may be 

 recognized by its striking secondary sexual characters. These 

 are well shown in Mr. Butler's figure of Th. proboscideus, and 

 a comparison between this and the same author's figure of 

 Hypoctonus formosus will show better than words can explain 

 the wide difference in the style of the sexual modification 

 between the two genera. 



Thelyphonellus, gen. no v. 



Carapace gradually narrowed in front to a point, not fur- 

 nished with ocular keels, the sides of the interocular area 

 being smooth and convex, as in Hypoctonus. The median 

 eyes lying flat upon the carapace, separated by a distance 

 which is about equal to a diameter, and not divided by an 

 upstanding ridge or tubercle. 



Genital operculum of the male large, swollen mesially, 

 polished, neither sulcate nor impressed, with its posterior 

 border almost evenly convex ; that of the female less swollen, 

 but also with evenly convex posterior border, and without 

 sulci and impressions. 



Ommatoids absent. 



Type Thelyphonellus an>azo?iicus (Butler): 



In addition to the female example from Santarem, which 

 served as Mr. Butler's type, the British Museum has five 

 more specimens which were collected in Demerara by 

 Mr. W. L. Sclater. Two of these examples are males, and 

 show that the chelae in this sex are much longer than in the 

 female. 



There is a transverse impression behind the median eyes, 

 and the anterior region of the carapace is f urnished with three 

 shallow longitudinal grooves. 



Length up to 25 millim. 



Revision of the Species identified or described in 

 Mr. Butler's Papers. 



S 2 ■ Th. giganteus, Lucas = Mastigoproctus giganteus (Lucas). 



$. Th. rufus, Butler = M. giganteus (Lucas). 



The colour of this specimen is a sign of immaturity and not of 

 specific distinction. 



