Three Genera of Papuan Passalid Coleoptera. 111 
larger than the right. The inner tubercles are well developped in fresh 
specimens. The margin of the canthus is more or less concave; when 
the concavity is very pronounced the anterior angles of the head and 
the external angle of the canthus are tooth-like, but this is not a constant 
nor even a usual characteristic of the species. The frontal area is usually 
about twice as broad as long, and rectangular or semi-cireular; but in 
the eight specimens from Squally Island, which are of a uniformly large 
size and probably belong to a single colony, it is three or even four 
times as broad as long. The parietal ridges extend directly outwards 
from a little behind the apex of the central tubercle, and are curved 
backwards at their extremities. The upper surface of the prothorax 
is smooth and unpunctured, except in the scars, and as a rule in the 
anterior angles, where the extent of the puncturing is very variable, and 
on the whole greater in small specimens than in large ones; the median 
Fig. 3A. 
Head of Omegarius minimus, KUWERT. x 4. 
groove is distinet and practically complete, the marginal groove is widely 
incomplete both before and behind. The posterior angles of the lower 
surface of the prothorax are finely punctured and hairy, the punetures 
and hair being continued as a rule along the outer margin of the other- 
wise smooth and hairless anterior angles, especially in small specimens. 
The seutellum is smooth and unpunctured except in the middle of the 
anterior margin. The mesothoracic episterna are punctured above 
and along the anterior margin; behind they are smooth and polished. 
The mesosternum is smooth and polished except in the scars which, though 
somewhat variable, are usually well developed, and matt wholly or in 
part. The lateral areas of the metasternum are narrow, parallel-sided, 
finely and closely punctured; the intermediate areas are more coarsely 
and less closely punctured on the inner side, smooth and unpunetured on 
tlıe outer. The posterior parts of the hind coxae are not strongly 
punctured; the abdominal sterna are more or less finely punctured in 
the scars. The elytra are hairless, and smooth except in the grooves, 
of which the outer are much more coarsely punctured than the inner. 
