Three Genera of Papuan Passalid Coleoptera. 109 
outer tuberele is obsolete, so that this tubercle appears to be simply 
pointed, and the head to be markedly asymmetrical. The ridges joining 
the inner tubereles to oneanother and to the outer tubercles are all obsolete 
or entirely absent. The rugosity of the anterior margin of the head is 
not quite so extensive as in H. zmpar, and does not extend on to the 
Fig. 20. 
Head of Hyperplesthenus gracilis (HELLER). >= 4. 
canthus. The parietal ridges are straight, and extend directly outwards 
or a little forwards. "The median groove of the pronotum may be either 
complete or incomplete in front; the scars contain hair-bearing punctures. 
The scutellum bears little or no trace of a median groove; it is punctured 
as in HZ. glaber. The mesothoracic episterna resemble those of H.impar. 
The scars on the mesosternum are absent or obsolete. The posterior 
intermediate areas of the metasternum may be smooth or more or less 
strongly punetured all over. The posterior parts of the hind coxae 
are almost entirely smooth. The elytra are unpunctured as in H. impar. 
Genus Omegarius, Kuwert. 
Anterior margin of head not markedly asymmetrical. Antennae 
with six well developed lamellae, all very long and slender. Dentition 
of mandibles variable; when reduced, the reduction is more marked on 
the left than on the right side. Scars on mentum semicireular, facing 
forwards, forming together a »&-shaped figure. Type, ©. pumelio (KAUP). 
KUWERT recognises two species of this genus, one from the Moluccas, 
and one from New Guinea; but the characters by which he distinguishes 
them are variable. I have seen a number of specimens from the Moluccas, 
New Guinea and New Brittain, some labelled with one name, and some 
