I9I4-] F. H. Gravely: An Account of the Oriental Passalidae. 311 



those found in the Himalayas, Assam, Burma aûd the Malay Peninsula as from those 

 found in Ceylon. Further, no Passalids are known from the dry hills of the Deccan 

 or from the northern parts of the Western Ghats ; and in the Himalayas only one species 

 appears to extend further west than the Darjeeling District, this being Ophrygonius 

 cantor i which has been recorded from the Dehra Dun District. 



There does not appear to be much to be learnt from the distribution of the 

 subfamilies in which asymmetry does not occur. 



Of these the Aulacocyclinae are at present centred towards the east of the Indo- 

 Australian area ; but the occurrence of a species of A ulacocyclus in the Indian Penin- 

 sula suggests that the subfamily may once have been commoner towards the west, 

 and some of the genera more widely distributed, than is now the case. The genus 

 Ceracupes is intermediate between the aberrant Chinese and Japanese genera Cylin- 

 drocaulus and Aurituhis on the one hand, and the rest of the subfamily on the other, 

 not only in certain structural peculiarities, but also in locality. 



The Pleurariinae occur only in the Indian Peninsula and Sumatra — a dis- 

 continuous distribution which also suggests that the subfamily formerly occupied a 

 more extensive area. 



The most curious features in the distribution of the Macrolininae are their 

 absence, so far as is known, from the Indian Peninsula, which contrasts strangely 

 with their abundance in all other parts of the Oriental Region, including Ceylon ; 

 and their occurrence outside the Oriental Region only in Celebes. 



The lycptaulacinae appear to be much rarer in the Indian Peninsula and Ceylon 

 (from which countries onl}^ the two commonest and most widely distributed species 

 are known) than in any other part of the Oriental Region.^ 



The distribution of the Aceraiinae and Gnaphalocneminae, in which asymmetrical 

 forms occur, is of much greater interest. 



The former subfamily occurs, usuall}^ in abundance, in all parts of the Oriental 

 Region where any Passalids at all are to be found, except the Andamans and Nicobars. 

 The distribution of the different genera belonging to it is peculiar. In Ceylon we 

 find the somewhat rare symmetrical species Episphenus moorei, which does not appear 

 to live gregariously as only isolated examples ever seem to have been found ; 

 and the slightly asymmetrical, abundant, gregarious, and highly variable species 

 Episphenus comptoni. In the Indian Peninsula we find two almost equally common 

 but more markedly asymmetrical species of Episphenus , E. indicus, and E. neel- 

 gherriensis. The former has the anterior angles of the head prominent, and resembles 

 Epis '^'henus comp oni in its gregarious habits and its great variability in size ; while 

 the latter has the anterior angles of the head obtuse and not at all prominent, and 

 resembles what little we know of the species of E. moorei in its less markedly 

 gregarious habits and in that all specimens are of an approximately uniform size. 



On the other side of the Gangetic Plain the symmetrical genus, Tiberioides , is 

 found, as a rarity, in the north only. Throughout the whole of the E. Himalayas, 

 Assam, Burma, Siam, Indo-China, the Malay Peninsula, and the Sunda and Philippine 

 ' See also below, p. 330. 



