1904.] Catalogue of the Coleoptera of South Africa. 59 



The characters distinguishing this genus from Trochalus are the 

 presence of a strong, hind ocular keel which either unites in a straight 

 line with the genal canthus or is not quite connected with it, in 

 which case it is slightly higher than the genal keel, and the presence 

 of a transverse clypeal keel edging the usually deeply depressed 

 anterior part of the clypeus the lateral margins of which are always 

 continued as far as the sharp apical angle instead of being produced 

 into a more or less sinuate keel above the margin of the anterior 

 part. 



The uniformity in facies and the enormous variation in colour 

 makes the study of the species a most difficult one, but the shape of 

 the genital armature helps greatly in the identification ; these arma- 

 tures are, however, so very complicated that it is difficult to give a 

 good description of them, and I greatly regret that I could not have 

 them figured ; the presence or absence of an additional antennal 

 joint helps also in grouping species which but for that character 

 would be hardly distinguishable. Cf. A, ditissimus and A. pavoninus 

 with A. crassus, &c. 



The distribution of species in South Africa is as wide as in the 

 genus Trochalus. 



Key to the Species. 

 A 2 . Antennas 10-jointed. 



B 2 . Hind ocular keel meeting the edge of the genal canthus. 



a 2 . Clypeal transverse keel not reaching the sides. 



Antennal joints of male free, clypeal keel very short . . ceneus. 

 a 1 . Clypeal transverse keel reaching from side to side. 



Clypeus strongly constricted laterally and tri-dentate. 

 b 2 . Anterior tibiae bi-dentate. 



Elytra deeply striate on the dorsal part ditissimus. 



Elytra slightly striate in the dorsal part pavoninus. 



b L . Anterior tibiaa tri-dentate. 



Bronze-black, with the upper side fleshy red . . . . crassus. 



Bronze-black, with a broad discoidal red band on each 



elytron . . . . nifovittatus. 



B 1 . Hind ocular keel not meeting quite the genal canthus. 



ft 2 . Clypeus strongly constricted laterally and tri-dentate in 

 front. 



b z . Frontal suture grooved. 



