452 Transactions Soutli African Philosophical Society, [vol. xii. 



Key to the Genera. 



Protliorax tuberculate, broadly' grooved in the centre ; elytra 

 with series of tubercles ; head only retractile Trox. 



Prothorax and elytra non-tuberculate ; whole body suscep- 

 tible of contracting into a ball Acanthocerodcs. 



Gen. trox, Fabr., 



Syst. Entom., i., 1792, p. 86. 



Phoherus, MacLeay ; Omorrjus, Erichs. 



Meiitum sub-ampliate laterally at middle, but attenuate more or 

 less obliquely towards the anterior angles ^Yhicll are sharp ; apical 

 part generally transverse, but also sub-emarginate transversely 

 (luridus, horridus), usually concave from the base to or past the 

 median part, and with the walls of the concave part more or less 

 sharply carinate, but also slightly concave at base only and distinctly 

 carinate in the middle {horridus, luridus) ; ligula slit in the middle, 

 moderately long in most species, but greatly developed in squalid us 

 and stiffly ciliate ; apical joint of labial palpi sub-fusiform, slightly 

 truncate at tip, nearly as long as the two basal ones put together ; 

 maxillae robust, apical lobe sub-falcate and armed with slightly curved, 

 unguiform, sub-corneous ciliae, inner lobe stiffly ciliate and armed 

 with two superposed falcate teeth the upper one of which is bifid ; 

 apical joint of maxillary palpi longer than the two preceding, fusi- 

 form but with the inner part a little more swollen than the outer 

 and slightly truncate at tip; mandibles flat underneath, robust, sharp 

 at tip, not entirely covered by the labrum which is briefly but 

 densely ciliate, and not incised ; clypeus small, more or less sharply 

 triangular, retractile, genaB sharply triangular and projecting; eyes 

 moderately large and not divided by the gense which form a lidge 

 above them ; antennas ten-jointed, basal joint very robust, stiffly 

 bristly in front, and nearly as long as the five following, second one 

 short, cylindrical, broader than the five following which are closely 

 set together ; club three-jointed, ovate ; prothorax deeply sinuate on 

 each side in front, arcuate laterally, and with the base truncate 

 laterally and triangular, convex, broadly grooved longitudinally in 

 the centre, and with one or more elongate tubercles or impressions 

 on each side of the disk, while the outer sides are plane and serrate ; 

 scutellum a little narrowed at base, and expanding into a lanciform 

 shape in the group of radula, &c., or not narrowed at base in the 



