ON THE CETONIID^ OF SOUTH AFRICA. 



13 



13. In this genus, generally, the terminal brush of the maxilla is inserted in the triangular 

 orifice of a short triangular corneous process, which terminates the maxilla, and appears articu- 

 lated to it. In some of the floral species, this pencil of hairs or brush is very long, and admirably 

 calculated for sucking up the honey of flowers ; but in other sub-genera, such as Platygenia 

 for example, the terminal brush may rather be considered to line the edge of the small trian- 

 gular corneous process which terminates the maxilla and appears articulated with it. In such 

 insects this process of the maxilla is not so palpiform as in those Trichini which inhabit flowers. 



14. The larva and metamorphosis of the sub-genus Trichinus have been perfectly well 

 explained by Professor Dehaan of Leyden, who shews that they bear more similarity to those 

 of Glaphyrid(B and MelolontMda, than to those of the sub-genus Cetonia. This is a curious 

 fact, and strongly illustrative of the danger attendant on our assuming a method of division 

 instead of following the mode of variation. What groundwork for a natural division, for 

 instance, appears more natural than metamorphosis ? Certainly none ; and yet if we divide 

 the family of Cetoniidce by this rule, we shall place half of the contents along with the 

 genus Melolontha! If, on the other hand, we follow the maxim of variation, and watch 

 how the metamorphosis changes, we only arrive at the fact, that Trichinus (i. e. an aberrant 

 genus of Cetoniidcc) is intermediate between the GlaphyridcB and the typical Cetoniidce, 

 inasmuch as it has the larva of the former, and the imago of the latter. 



But we proceed to detail the various sub-genera of Trichinus. Fabricius was not acquainted 

 with the singular insects which compose the first of them. 



A.— Body depressed and sides thin, ['i Platygenia, M'L. 

 First joint of maxillary palpi^ 

 distinct. Campulipus, K. 



B. — Body and sides thick. First 

 joint of maxillary palpi eva-< 

 nescent. 



^3 Trichius, M'L. 

 4 Valgus, Sc. 



Anterior tibiae externally bidentate. 

 Anterior tibise externally tridentate. 

 f Anterior tibise externally bidentate in general. Body 



^ covered with hairs or scales. 



^Anterior tibise externally multidentate.^^ Body spotted 



with scales. 



f Anterior tibise externally tridentate. Body depressed, 

 5 OSMODERMA, Lp. Sr. < 



I without hair or scales. 



Sub-genus 1. Platygenia, M'L. 



15. Of this sub-genus only one species is certainly known ; although, to say the truth, 

 Gory's figure of what he calls Platygenia Zairica, is so unlike the insect which I so named 

 some years ago, that one is almost inclined to believe he may have fallen accidentally upon 

 a new species of the groupe. Indeed, I consider the Trichius harhatus of Schonherr to 

 belong certainly to the sub-genus. The mouth of Platygenia approaches very near in 

 structure to that of Osmoderma, however different it may seem in external appearance. It 

 is in fact, the mouth of an Osmoderma, with all the parts flattened, and excessively 

 widened, differing only in having the terminal lobe of the maxillse transversal and small. I 

 imagine, indeed, that the true character of this sub-genus is founded on the comparative 

 evanescence of the palpiform terminal process of the maxillae. 



16. The general form of the thorax of Platygenia, and its very depressed body, make me 

 think that we can proceed from it to Campulipus, by means of some sections hitherto 



