187 



gates found their subdivision on the presence (a) of three 

 joints only, (b) of more than three joints, in the antennal 

 flabellum, which seems to be a more important character in 

 this group than it is in the Sericoides. 



It may be noted here that Rhopcea is extremely close to 

 the Fabrician genus M elolontha . Lacordaire distinguishes it 

 from the latter by there being an additional lamina in its 

 antennal flabellum (which is certainly not a valid generic 

 character), and adds that it is of more cylindric and parallel 

 form, that its pygidium is slightly emarginate in the female 

 (in Melolontha he calls the hind margin of the pygidium "of 

 variable form"), and that it has no trace of a mesosternal 

 process (in tabulating Melolontha he places it in the aggre- 

 gate "no mesosternal process," but in the diagnosis of the 

 genus says that its mesosternum is "slightly prominent"). I 

 have before me M. vulgaris, Fab., which is, I believe, the 

 typical species of the genus, and fail to discover in it any 

 mesosternal process on which to found a generic distinction. 

 Its extraordinarily produced pygidium is totally different 

 from the pygidium of any known Rhopcea, but Lacordaire 

 states that that elongation is wanting in some other European 

 members of the genus. In fact, the only character that I 

 can find (likely to be generic) constant in Rhopcea distinguish- 

 ing it from M . vulgaris (now before me) and from the con- 

 stant characters of Melolontha as stated by Lacordaire is in 

 the claws, their tooth being in Rhopcea much larger and 

 placed at a considerably greater distance from the base of the 

 claw than in Melolontha. 



I may now pass on to show in tabular form distinctive 

 characters for those aggregates of the "Groupe" "true 

 Melolonthides" which in my opinion should be regarded as 

 valid genera, so far as concerns the Australian Fauna. I 

 am doubtful, however, whether the species that I attribute 

 to Lepidiota ought not to be divided into more than one 

 genus; but since Lepidiota is of very wide distribution, and 

 Australia does not appear to be its headquarters, a wider 

 knowledge than I possess of the species occurring outside 

 Australia should be at the disposal of an author to enable 

 him to deal satisfactorily with that question. 



A. Front face of clypeus rugulose, and set 

 all across with long soft hairs ; dis- 

 tance from its base to its summit 

 about equal to the length of the 

 apical joint of a maxillary palpus. 

 B. Antennal flabellum consisting of 

 more than 3 joints. 

 C. Labrum vertical* or nearly so. 



