852 Mr. F. O. P. Cambridge on ike 



$ . — Colour. Carapace dull nialiogany-brown, with broad 

 lateral marginal pale band, their inner margins subparallel, 

 extending from exterior angles of clypeus to the base. Abdo- 

 men dark olive-brown above, with broad marginal pale yellow 

 band extending from anterior shoulders to spinners. Uni- 

 colorous beneath. Mandibles unicolorous brown. Legs and 

 palpi pale ochreous. Tibiae, protarsi, and tarsi clothed with 

 line lateral barbules (curving hairs, such as are found on tlie 

 feathers of young birds). Protarsi and tarsi clothed with 

 dull yellow-white pubescence above, more conspicuous than 

 on other segments. 



Structure as in generic diagnosis. 



Vulva broader than long (PI. IV. fig. 18). 



A single female in the Natural History Museum from 

 Borneo. 



Thalassius DohschalUi^ sp. n., ? ad. 

 (PI. IV. fig. 19.) 



Type in coll. Brit. Mus. Nat. Hist. 



Hah. Borneo. 



? ad. — Tot. len. 20*5 mm., carap. 7*5 X 6*5 ; legs i. 40, 

 ii. 40, iii. 36*5, iv. 41'o ; pat. + tib. i. and ii. 13, iii. 11*5, 

 iv. 13*5 ; prot. i. and ii. 8"5, iii. 8, iv. 9*75. 



5 . — Colour precisely the same as in the last species, but 

 the colour of the dorsal area between the white lateral bands 

 is rich chocolate-brown and the legs are shorter in proportion 

 to the trunk. 



Structure as in generic diagnosis. 



Vulva longer than broad (PI. IV. fig. 19). 



A single female in the Natural History Museum from 

 Borneo. 



The two species may be determined by the following 

 table : — 



A. Size larger, 23 mm., car<apace 10*o, leg iv. 60. 



Central anterior eyes distinctly larger than 

 central posteriors. Vulva broader than long. 

 Basal disk oval-oblong, with transverse fold 

 near posterior margin T. Stmoni, sp. n. 



B, Size smaller, 20"5 mm., carapace 7*o, leg iv. 41-5. 



Central anterior eyes equal to central poste- 

 riors. Vulva longer than broad. Basal disk 

 triangular, without any transverse fold T. Doleschallii, sp, n. 



Species assigned to Thalassius, Sim. 



1885, Thalassius marginelluSj Sim. Spec. juv. Bull. Soc. 

 Zool. Fr. X. p. 13, 

 M. Simon notes an immature example of the genus Thalas~ 



