194 Annals of the South African Museum. 



Measurements. — Total length 43 ; lengthof cephalothorax4-7,of tail 

 24-5 ; length and width of first caudal segment 2-8, 2-9, of second 

 segment 3-4, 2.7, of third segment 3-5, 2-6, of fourth segment 4-4, 

 2-6, of fifth segment 4-8, 2-6, of sixth segment 4-9, 2-3 ; length of 

 tibia of pedipalp 4.5, 1.9 ; width of hand 2-2 ; length of hand-back 

 3'3, of movable finger 4-6. 



Besides being relatively shorter, the second, third, and fourth 

 •caudal segments in the 2 of lineatus and insignis appear more 

 ■convex at the sides from before to behind when seen from above ; 

 in marlothi these sides are almost parallel. The granulation on the 

 under surface of the fifth caudal segment in marlothi is about as 

 ■coarse as, although much denser than, that in a ? lineatus from 

 the Cape Peninsula. 



U. marlothi is closely related to U. insignis, from which it may be 

 distinguished by the total absence of the infero-lateral crest or edge 

 in the fifth caudal segment. 



Gen. OPISTHOPHTHALMUS C. L. Koch. 

 Opisthophthalmus wahlbbrgi (Thor.) 



Three local races of this species, differing in the colouration of the 

 tail, may be distinguished : — 



a. 0. luahlbergi (typicus) with at most the fifth caudal segment 

 blackened towards the apex, the rest of the tail being yellow. 



This agrees with the description Thorell gives of his spirit specimen 

 from the Stockholm Museum, which is said to have been found by 

 Wahlberg in " Caffraria " and may be taken as the type. The South 

 African Museum possesses three specimens from German South- 

 West Africa {Dr. B. Marloth), in one of which (a young $ ) the fifth 

 caudal segment is lightly infuscated on the sides and below in the 

 posterior half, while in the other two specimens (described in Ann. 

 S. A. Mus., V. 1, p. 140) none of the caudal segments are blackened. 

 This form is not known to occur south of the Orange Eiver, and 

 Wahlberg's specimen doubtless also came from German South- West 

 Africa, probably from Damaraland, whence the species has been 

 recorded by Kraepelin and Pocock.-'- 



/3. 0. loahlhergi var. gariepensis, n., with the fourth caudal seg- 

 ment more or less blackened on the sides and below, the fifth 



* 0. ivahlbergi has also been recorded from British Bechuanaland by Penther 

 (Ann. Naturh. Hofm. Wien, v. 15, p. 158, 1900), but no mention is made of the 

 colouration. 



