642 REVISION OF THE «;enus pakopsis, 



For secondary and tertiary divisions I have found the most 

 vahiable characters in the margins of the prothorax, and the 

 structure of the humeral regions of the elytra. In many species 

 the transverse convexity of the prothorax is even (independently 

 of the evenness or otherwise of the surjace), i e., the convexity of 

 the disc continues unchanged to the extreme lateral margin ; in 

 the rest of the species the convexity becomes less strong on a 

 more or less wide marginal space. In these latter I call the pro- 

 thorax " explanate at the sides." On the elytra the area between 

 the humeral callus and the lateral margin presents two aspects, — 

 in some species being flattened (or even concave) so that (looked 

 at from a certain point of view) there appears to be a space 

 (roughly triangular, the humeral angle of the elytron Ijeing the 

 apex of the triangle) on a more or less different plane from that 

 of the general surface ; in the other species this portion of the 

 elytra continues quite uninterruptedly the general plane of the 

 surface. I characterise the former of these aggregates as 

 "depressed under the humeral callus." 



Another character calling for remark is the relation of the 

 marginal portion (which is the external surface of the epipleune) 

 of the elytra to the disc. In most species the distinction between 

 these is indicated b}' a lightly impressed ill-defined longitudinal 

 concavity (generally most noticeable for a short space near the 

 apex). I have called this concavity the " submarginal sulcus." 



And yet another character I'equires comment, viz., the structure 

 of the epipleuras of the elytra. These consist of an inner more or 

 less horizontal piece (generally a mere fine line in its apical half) and 

 an external more or less vertical piece. The height of the external 

 piece varies greatly in different species, but is very constant in 

 tlie individuals of a species. Its height, however, is so difficult 

 to express profitably in words that I have had to fall back ui>on 

 characterising its indication on the upper surface. According as 

 it is more or less high, the lateral margin is further from or 

 nearer to the humeral callus, so that in species with the external 

 piece of the epipleurje greatly elevated the inner edge of the 

 humeral callus is as far from the external margin of the elytra as 



