3-2^ Memoirs of the Indian Museum. [Vol. Ill, 



text-figs. 8A& B. The right outer tubercle is very deep and broadly truncate as seen 

 from the side. The outer portion of the left outer tubercle is exactly like it ; but be- 

 tween this and the middle-line is a large rounded process which does not occur on the 

 right side. The surface of the head between the outer tubercles and the supraorbital 

 ridges is more or less level, not excavate. The apical angles of the supraorbital 

 ridges are very distinct, of about 120°, and slightly peaked. The pronotum is un- 

 punctured except in the marginal groove and in the small, round, hairless .scars. The 

 marginal groove is broadly incomplete before and behind; but the median groove, 

 which is deeply impressed, is practically complete. The plates of the loioer side of the 

 prothorax bear punctures and hair distributed as usual in the family, but not so 

 thickly or extensively as sometimes. The scutellum is very indistinctly punctured all 

 over ; the mesothoracic epistcrna are coarsely punctured above and along the anterior 

 margin ; the mesosterntim is highly polished throughout, except in the deeply im- 

 pressed semi-lunar scars, and even these are scarcely dull. The lateral areas of the 

 metasternum are narrow, parallel-sided and slightly roughened ; they are very sharply 

 -separated from the anterior and posterior intermediate areas, which are broadly 

 continuous with one another, and are coarsely punctured except along their outer 

 margins. The posterior coxae are smooth. The scars of the abdominal sterna are 

 more or less roughened and punctured. The elytra are hairless, and are unpunctured 

 except in the grooves, of which the lateral are much more coarsely punctured than 

 the dorsal, their punctures being, however, scarcely transverse. 



The systematic position of this form is somewhat difficult to determine. The 

 structure of the anterior margin of the head at once suggests relationship with the sub- 

 family Gnaphalocneminae ; and the Aceraiine form of mentum seems to place it near 

 the genus Hyperplesthcnus. In Hyperplesthenus and all other genera of the group to 

 which it belongs, however, the lateral and intermediate areas of the metasternum are 

 fused, whereas in Pseudepisphenus no trace of any such fusion is found; and all 

 known species of the Hyperplesthenus group are much larger insects than Pseudepis- 

 phenus perplex us. 



In size and general appearance, Pseudepisphenus resembles rather the Protomo- 

 coelus group, the simpler members of which have, like it, a metasternum of the ordinary 

 type. The possibiUty of the absence of primary scars from the mentum in this group 

 has been pointed out above (p. 194, footnote) ; and it is quite likely, I think, that in 

 Pseudepisphenus we have a case in point. 



Although the precise systematic position of Pseudepisphenus is open to this much 

 doubt, its asymmetry and consequent obvious connection with some group of the 

 Gnaphalocneminae are of great interest on account of its apparent affinity, on the other 

 hand, with the aberrant genus Tarquinius. The peculiar structure of its mandibles 

 is essentially the same as that found, so far as I know, in Tarquinius alone of all 

 Indo-Australian Passalidae. The chief difference between the mandibles of the two 

 genera lies in the fact that the peculiar external keel is more strongly emphasized in 



