350 , Mr. F. 0. P. Cambridge o?i the 



marginal portion lies a sliort, rather slender tooth, its apex 

 directed inwards (PI. IV. fig. 1). 



A single female from tlie Museum collection, taken by 

 Dr. Cuming at Manila, Philippines. 



(iv.) Genera and Species of S-cIaived Forms, loi'th Notes on 

 Types and Descriptions of New Species. 



1858-59. Dolomecks, Walck., Dolesch. Verhand. nat. Ver. Ned. Ind. v. 

 p. 9. 



1884. Titiirhis, Sim. Ann. Mus. Genov. xx. p. 328. (Type T. fmhnatus 

 (Walck.), 5 . — Cape of Good Hope, S. Africa.) 



1885. 77/«/fl.ss/M,<f, Siui. Bull. Soc. Zool. Fr. p. 13. (For Titurius, noui. 

 praeocc.) 



1891. T)olnp(£us, Thor. Konol. Sv. Vet.-Aliad. TIandl. xxiv. (2) p. CO. 

 (Type D. cinctus, Thor., j . — Isl. Kamorta, Nicobar, Bay of Bengal. ) 



Of the type of ThaJassius, Sim., I know notliing, but I 

 have been able to examine a sjiecimen from South Africa 

 (Umfali Kiver) which undoubtedly belongs to this genus. 

 The type of a species named Thalassius unicolor by Simon 

 himself, from Sheik Husein, is also before me, so that one 

 can speak without hesitation on the characters of Thalassius, 

 Sim. 



The species described below as DoJeschaUii and Simoni 

 from Borneo are undoubtedly congeneric with Thalassius 

 vnicolor, Sim. Three immature forms from Tenasserim and 

 "J'harrawaddy, Burmah (e coll. Gates), referred by Tliorell to 

 Thalassius alhocinctus (Doles.), are identical with the form 

 to which I have given the name Doleschallii. I cannot 

 regard it at present as possible to tell what form Doleschall's 

 alhocinctus may have been. It is not at all likely that there 

 is only one form Avitli broad yellow-white bauds found 

 in Java, Borneo, and Burmah. I should fully expect four 

 or five closely allied forms to be found on a more extended 

 search. Then it might be possible to identify alhocinctus as 

 that form which is found in Java exclusively, though even 

 then there might be in this island itself two or three forms 

 similar in general characters, differing only in the form of 

 the vulva ; and in this case the identity of alhocinctus would 

 be next to impossible to settle. I am confident that the 

 absence of figures of these important structural points will in 

 future render a great deal of descriptive work almost useless. 



In the form described as T. Simoni the anterior central 

 eyes are distinctly larger than the ])osterior centrals, and the 

 clypeus is lower in proportion ; but none the less I am 



