of Petalocerous Insects. 151 



Corpus depressum. 



M. La(reille appears to have hesitated much as to the natural 

 statiou of this genus. At first he placed it at the head of his 

 Scarabeides with membranaceous mandibles, immediately before 

 Trichius*. In his Considerations^ &c. J it follows that genus. 

 In the Regne Animal it closes the petalocerous genera +, and is 

 succeeded by Lucanus. Again in the XXXth Volume of the 

 Nouveau Dictionnaire D'llistoire Natiirelte, published two years 

 afterwards, it resumes its former station after Trichiiis',\\ and 

 lastly, in his Families Naturelles Dn Ri'gne Animal, it forms 

 the second genus in his Family oi Melituphili, being preceded by 

 Platj/genia, which also is remarkable for a large concave /a6/«?H,§ 

 and followed hj Goliathus.*'^ It appears to form an osculant genus, 

 as well as (he preceding one. Its Mandibulce corneous, with the 

 exception of a dorsal lobe of membrane, and its corneous Maxilla 

 armed with spines, prove that it is of that description, and its 

 general habit and characters, that it is nearly related to the Tri- 

 chiado!, and that it connects M. Latreille's Melitophili with some 

 other family in another circle. Cnemida indeed in some respects 

 seems without the circle of Riitelidce, and may be also regarded as 

 osculant. If we look at the remarkably depressed body oWrenuis- 

 tocheilus and its quadrangular prothorax, we find an analogy 

 between it and some of the ScarahceidcB M'L. particularly 

 amongst the Onitidx, where a remarkable genus from South Ame- 

 rica, named by Mr. MacLeay Eutomus, exhibits considerable re- 

 semblance at first sight to it. It has one character in common 

 with the Dynastida;, which is only to be met with in one other 

 petalocerous genus, as far as my examination of them goes, the 

 prosternum is nearly vertical, forming a kind of pectoral horn, 

 before the base of the arms, or fore legs. 



Canaliculatus. 3. C. niger, prothorace canaliculato : angulis pos- 

 ticis magis extantibus dentiformibus. 



• Gen. Crust, et Ins. ii. 121. | p, 198 f iii. 288. || Article Scarnbcides, 

 302, This volume was published in 1819, and the third vol. o^ Regne .Animal, 

 in 1817. (j IJor. Entomolog. t. iii. f. 23. F. The part here called the Labium 

 is #lic Mentum of Messrs. Latreille and MacLeay. See Introd. iii. 355. B. & 

 420—25. ** Fam. Nat. 371. 



