igi4.] F- H. Gravely : An Account of the Oriental Passalidae. 'Ly() 



The Indian Museum collection of Passalidae was first arranged by Dr. Stoliczka, 

 who published an account of it in 1873. He himself presented a considerable 

 number of the specimens which it contains. Many of these specimens belonged to 

 und escribed species; and Stoliczka's descriptions of them added considerably to the 

 knowledge of the family. Had he lived to discuss Kaup's classification (published in 

 1871), as he proposed to do in the monograph he was planning, there can be little 

 doubt that it would have been greatly to our present advantage. Owing to his early 

 death on his way back from Central Asia it happened that Kuwert was the first to 

 attempt a revision of the family. Unfortunately Kuwert appears to have been 

 anxious merely to define briefly and conveniently genera and species, and not to 

 have cared greatly for the problems of phylogeny or distribution ; consequently he 

 failed to show some of the close relationships that exist among Indo-Australian 

 forms, giving an undue value to the presence or absence of asymmetry in the head, 

 at the expense of other characters which seem to be really more important. 



The value of Kuwert's posthumously published work is further reduced by the 

 fact that it had evidently not received its final revision at the time of his death ; 

 so that the text is in parts very difficult to follow, and some of the figures appear 

 to be unfinished, while others are either wrongly numbered or incorrect, unless his 

 descriptions of the genera they represent are wrong. Nevertheless, his paper includes 

 by far the most complete classification in existence. 



2. EXTERNAIv ANATOMY WITH SPECIAIv REFERENCE TO THE 

 TAXONOMIC VALUES OF DIFFERENT PARTS. 



As yet no one appears to have made a study of the relative values, for diagnostic 

 purposes, of the various parts of a Passalid beetle. Instead, it has been assumed 

 that all specimens differing markedly from one another in size or in such conspicuous 

 characters as the form of the various ridges of the head, necessarily belong to 

 different species. Zang (1905a, pp. 163-4) has, indeed, pointed out how misleading 

 variations in the ridges of the head may be in specimens belonging to the genus Chilo- 

 mazus ; but even he failed to notice that this had been a constant source of difficulty 

 in other genera as \yq[\. As the views I have been led to adopt by my work on the 

 collections described below have caused me to suggest considerable reductions in the 

 number of recognized species, I propose to state them here in giving an account of 

 the terms used to designate the different parts of the insects. 



the British Museum, aud I have to thank Prof. KraepeHu, Prof. Von Brunn, Herr Gebien, Dr. Horn and 

 Mr. Arrow for the help they gave me when studying these coll-ections. I have aho, through the kindness 

 of Mr. René Oberthür, and the Directors of the Museums at Darmstadt, Dresden and Stuttgart, 

 received for examination certain of the type specimens preserved in their collections. As a result 

 of this I have been able to complete this paper by the inclusion of keys to all species known from 

 the Oriental Region, and to Australian genera ; to examine a number of specimens named by 

 Kuwert; to complete my account of the widely-distributed Oriental genus Aceraius by notes on 

 Zang's species, most of which I had not previously seen ; and to add to and improve the paper in 

 several other respects. 



