319 



myself of the existence of structural characters that could be 

 relied upon as generically invariable. These are of oval form, 

 and are much less elongate than any of the above mentioned 

 genera, their shape being suggestive of Harpalus and in some 

 cases of Choleva, while Hyhrenia, &c., approximate more to the 

 appearance of Tele'phorus, or Tenehrio. I have spent some time 

 in examining these insects in search of a workable method of 

 defining this distinction provisionally until the comparison of 

 both sexes of a large number of species be possible (which will 

 probably lead to a much more scientific diagnosis), and have 

 found that this difference in facies seems reliably associated with 

 a difference in the comparative length of the femora and width 

 of the body. In Homotrysis, Hyhrenia, &c., the hind femora, if 

 laid out at right angles to the central longitudinal line of the 

 body, extend by at least a third of their length beyond the 

 external margin of the elytral epipleur^e, while in these more 

 oval forms the projecting piece of the femora similarly jDlacecl is 

 much shorter. In these latter, also, the head, as compared with 

 the prothorax is very much narrower. I find it necessary to 

 characterise two new genera for them, as there are two very dis- 

 tinct types among them differing in the general facies and in the 

 structure of the femora. I divide the Australian genera of 

 Cistelidce with bifid mandibles as follows : — 



A. Hind femora much longer than the distance 

 from their base to the external margin of 

 the elytral epij)leur?e. 

 B. Apterous ... ... ... ... ... Metistete 



BB. Winged Homotrysis 



AA. Hind femora little (or scarcely) longer than 

 the distance from their base to the external 

 margin of the elytral epipleurpe. 

 B. Tibial depression beneath femora very long. 



Facies of llarpalides ... ... ... Scaletomerus 



BB. Tibial depression beneath femora much 



shorter. Facies of ChoJeva or Platydema Nocar 



Homotrysis (as T regard it) has been subdivided thus (assuming 

 Haag-Rutenberg's species to have mandibles bifid at the apex) : — 



A. Apical joint of maxillary palpi of ordinary size. 

 B. Eyes approximate. Prothorax closely ap- 

 plied to elytra ... ... ... ... Hybrenia 



BB. Eyes more distant. Prothorax less closely 



fitted to elytra ... ... ... ... Homotrysis 



AA. Apical joint of maxillary palpi very large ... Lisa 



Finding myself unable (as already pointed out) to determine 

 to which of Hybrenia, Homotrysis, and Lisa should be referred 



