16 



ON THE CETONIID^ OF SOUTH AFRICA. 



Sub-genus 4. Valgus, Scriba. 



23. This answers to the genus Acanthurus of Kirby, easily known by its depressed form, 

 long trapezoidal pro thorax, and short elytra. In the only section of this sub -genus which 

 I know, there is a mucro arming the anus in one of the sexes, and which is probably the 

 ovipositor. I have always found the species of Valgus, either at the roots of trees, or at the 

 foot of walls, but never on flowers as Latreille says that he has found them. The section 

 Geometrici of the last sub-genus is covered with scales, and so is this sub-genus ; but we still 

 want some sections of Valgus to connect the Geometrici with the common Trichius Jiemipterus 

 of Fabricius. Indeed, I am not aware that the present sub-genus has ever been resolved into 

 sections. There is one species at the Cape, viz. 



Sp. 6. (Trichinus) Valgus Smithii, n. s. 



Descr. Valgus thorace postice utrinque macula nigra abdominisqiie fascia alba. 



Long. Corp. 4 lines. 



Note, This species is scarcely distinct from the Valgus Jiemipterus of Europe. It has the same rugfe 

 of the thorax, the same size and general form, and only differs slightly in the disposition of the scales. 

 In V. hemipterus for instance, the abdomen is quite white with thickly set scales. In V. Smithii there is 

 merely a white band. V. Smithii has also a white mark in the black lateral spot of the thorax. But in 

 truth these species come very near to each other. 



Sub-genus 5. Osmoderma, Lp. Sr. 



24. This groupe has been hitherto described and figured with little care. It is said to 

 have the terminal lobe of its maxillse corneous. This lobe is not, however, more corneous than 

 in any of the other sub-genera of Trichinus. It is an elongated hollow triangle, filled with a 

 short thick pencil of hairs. The true characteristic of the sub-genus is the strong corneous 

 hook which arms the maxillse on its inner side. These insects live with their larvse in rotten 

 wood. They have been called Gymnodi by Mr. Kirby, and made by him part of his genus 

 Trichius. I am acquainted with two sections of Osmoderma, which are peculiar to Europe 

 and North America. The type is Trichius Eremita of Fabricius. I have already said that, 

 different as Platygenia Zairica is in aspect from all the other known species of the genus 

 Trichinus, it comes in every essential respect exceedingly close to Osmoderma. I suppose the 

 name given by Lepelletier and Serville to this sub-genus, alludes to the scent of Russia 

 leather, which the European species O. Eremita emits when it is handled. 



Genus II. CRYPTODINUS, Mihi. 



25. We have seen that none of the known species of the genus Trichinus have the terminal 

 lobe of their maxillse furnished with teeth. The sub-genus Osmoderma, was indeed sup- 

 posed to possess this structure, but erroneously; although it has certainly a tooth at the 

 point of the inner process. This formation appears to prepare us for the maxillse of the 

 present genus Cryptodinus, of which the character is always to have a corneous tooth or 

 teeth on the terminal process. Indeed, that tooth which Osmoderma possesses on the inner 

 process of the maxillse, brings it, of all the sub-genera of Trichinus, the nearest to the genus 

 Cryptodinus. This genus may be always known by its depressed elongated form, and by 

 the under side of the mentum having a process, while the outer side of the terminal process 

 of the maxilla has no brush. Cryptodini are found in all the principal divisions of the 

 globe, Europe excepted. They are nevertheless chiefly intratropical insects, which are 



