l'MH.\ V. II. (Jkavklv : I'msaUdae <il thr Worhl. I2a 



The tliird and last line f)t descent I'loni MastocJiilus is found in the genera 

 PsciKiciiisiilinnis aiul Taninitiins, two extremely rare forms known only from New (.luinea. 

 Their atlinities have already been fully discussed elsewhere ((iravely, 1924c, 328-329). 



The Leptaulacinae are centred in the Malayan Sub-Region, whence several have spread 

 westwards and eastwards to the Indo-Chinese Sub-Region and Celebes respectively. The two 

 dominant .species, L. bi col or and L. dentatus, have spiead beyond these limits into the Indian 

 Peninsula and Ceylon in the west, and into the Moluccas, New (luinea, and possibly even 

 Australia in the east. Isolated species have arisen in several of the islands or island groups 

 of liotli the eastern and western parts of the archipelago. The number of distinct species 

 appears, however, to be small and tlie more widely distributed species especially are 

 extremely variable and often dillicult to distinguish from one another. They are also 

 extremely abundant. This probably indicates that the subfamilj- is of relatively recent 

 origin and that it has not yet reached a condition of equilibrium. 



The importance of Palk Strait, the Gangetic Plain, the China Sea and Isthmus of Kra 

 (together), the Straits of Macassar and Torres Strait in the di.stribution of the MacroliTjinue 

 has already been pointed out (Gravely, 1914c, p. 338). The further study of the Pa.s.salidae 

 of the Australian Region shows that the Molucca and Gilolo Straits are of no less 

 importance and, indeed, that to the former belongs tlie special importance which I 

 previously attached to the Straits of Macassar, tlie fauna of Celebes being even more 

 unlike that of the AustraUan Region than it is unhke that of the Oriental Region. 



The Passalids hitherto recorded from Celebes are as follows '.^ — 



r, t IT \ (Genus otherwise purelv Orieatal : C. foveicoUis, 



L o»iaciipes fovocnllis »\ibf^p. ninwr . . -l ^ ■ ' ' 



( «. str., confined to Borneo. 



Aulacocyclus celebens>s . . Endemic. Genus Indo- Australian. 



-, ,. , . , (Endemic. Belongs to the inroup of ilffjcro/on/s other- 



Macrohmis sulaperfectus . . , . , , , T ,, , ^ , ■ 



( wise known only from the Malayan Subregion. 



„ duivenbodei . . . . ) 



.These two constitute a {jroup which is endemic. 



Aceraivslaev,colUs .. .. ^'^ Malayan species. The genus is so definitely 



( Oriental that I am inclined to doubt this record. 

 PlesUienus s])p. .. .. Endemic. Allied to the Oriental Pe/o/firffA-. 



Trichosligmus ursulus .. .. (Endemic. The only other known species of the 



( genus is Oriental. 



Leplaulnx planus . . . . . . ^ 



... /Oriental species which appear to be extending their 



',', a,cloLnius '.'. \ '"""-''• ^"^ ** •^*"* '"'" ''''''^^^ ^^^' *'"'»*^'^ 



., dentatus .. .. ) a"d pos.sibly Au.stralia. 



Although a large proportion of these species are endemic, and it is doubtfid whether 

 either of the two most characteristic asymmetrical Oriental genera, Accmins and Pelopi'd4.'s, 

 occur in Celebes at all. it will be seen that every species known from Celebes is related to 

 species which are essentially Oriout.il. although some have establi.^hed themselves in the 

 Australian Kegitm also. 



» Concerning Knwert's ipcoril of " Tf/o/w " imprctsieollis see nbovo. |>. 107. footnote 2 



R -2 



