1900.] Catalogue of the ColcoiAcra of SoiitJh Africa. 453 



Jioriidiis group; elytra fitting against the prothorax, very convex, 

 elongate, but v^rith the humeral angles quite rounded and sloping 

 and covered with series of more or less densely fasciculate tubercles ; 

 abdomen five-jointed, joints not flexible ; legs moderately robust, 

 anterior femora strong, anterior tibiae moderately slender, tri-dentate 

 externally, but with the upper tooth situated at the apex of the 

 tiiaia, and separated from the second by a shallow transverse sinua- 

 tion, inner angle provided with a strong, slightly incurved spine, 

 these anterior tibia? are also more or less distinctly piuri-serrate 

 above the digitation ; intermediate and posterior tibiae hardly 

 thickened at tip, quadrangular, or with five ciliate caringe, and 

 without any transverse ridges, apical spurs slightly unequal, tarsi 

 short, a little compressed on the upper part, more or less bluntly 

 triangular, claws moderately long, and not weak. 



The South African species of the genus can be divided into two 

 groups according to the shape of the metasternum which in the 

 first, of which horrid us is the type, is produced into a triangular 

 elongate process between the intermediate coxae and nearly meets 

 there the sharp apical point of the mesosternum, or which in the 

 second, of which incultus is the type, does not project between the 

 coxae to any appreciable degree. 



The genus Phoberus was established by MacLeay for the reception 

 of Trox horrldus, the main characteristics of which were the absence 

 of wings, and the non-crenulate intermediate and posterior tibiae 

 having five rows of stiff bristles. Burmeister (Stettin. Entom. Zeit., 

 vol. xxxvii., 1876, p. 264) retains the genus chiefly on account of 

 these characters, and also on account of the arcuate pro thoracic base 

 having no median lobe in front of the scutellum. This latter 

 characteristic does not, however, apply to all the species which might 

 be included in Phoberus owing to the five carinated tibiaa lieing 

 ciliate, and which do really form a distinct group of closely allied 

 species peculiar to the western part of South Africa, several of which 

 are wingless. 



To the genus Trox Burmeister restricts the species with quad- 

 rangular serrate hind legs and a triangular or ogival scutellum, and 

 to the genus Omorgus the species with quadrangular serrate hind legs 

 and a scutellum strangulated at base and dilated from there in the 

 shape of a lance-head. 



It is worthy of note that in the first and second of these divisions 

 the forceps and valves of the genital armature of the male are much 

 more elongate than in the third where they are short and broad and 

 less variable in shape. On the other hand, T. incultus has the 

 posterior tibiae with five non-ciliate carinas, and the scutellum strongly 



