326 Transactions South African Philosoiolncal Society, [vol. xii. 



Cephalic horn short, laminate and sub-quadrate at base, 

 apical part curving forward ; space between the prothoracic 

 horns excavate and smooth dubius. 



B^ Prothorax more or less excavate in the middle of the 

 anterior part. 



Clypeus with the angles of the median emargination very 

 long and recurved ; cephalic horn laminate and quadrate 

 at base, narrowly sub-cylindrical at tip and curving 

 inwards ; prothorax with a conspicuous apical tubercle on 

 each side of the excavation (pi. xxxiii., figs. 21, 22) . . . . melancliolicus.^ 



Clypeus with the angles of the emargination not recurved ; '^ Av --^ <^ Y^ \ 

 head and prothorax as in 7?icZmic/ioZic?<s marcellus. 



A\ Anterior tibise not oblique at tip, and strongly spinose ; 

 inwardly in the male. 

 B. Prothorax not truncate in front, and regularly convex in 

 both sexes. 

 C~. Apical spur of anterior tibise straight. 



Clypeus with the angles of the median emargination 

 very distinct ; cephalic horn short, triangular ; prothorax 

 abruptly truncate, and with a shallow median impres- 

 sion (pi. xxxiii., fig. 6) opacus. 



Clypeus slightly emarginate at middle, but not recurved 

 nor angular ; prothorax scabrose except for a small 

 punctulate, posterior area latifrons. 



Clypeus slightly emarginate at middle, but not recurved 

 nor angular ; prothorax finely and equally punctured 

 except on the sides troglodytes. 



Clypeus deeply incised at middle, with the angles very 



sharp and recurved exiguus. 



C^ Apical spur of anterior tibise curved inwardly. 



Clypeus moderately emarginate at middle, prothorax 

 distinctly scabrose, except in the median part of the 

 base ; not impressed anderseni. 



CatHAESIUS PLA-TYCERUSfKlug, 



Monatsb. Ber. Acad., 1855, p. 655, Peters' Eeis. n. Mossamb., 1862, 



p. 240, pi. xiii., fig. 7. 



C. obtusicornis, Boh., Insect. Caffr., ii., p. 217. 



Piceous black, but having sometimes dark chestnut elytra. 



Male : Head semicircular, slightly emarginate in the centre of the 

 clypeus, with the gense projecting sensibly beyond the lateral part of 

 the clypeus, covered with distinct, small granules, and bearing in the 

 centre of the clypeus a flat, parallel tooth slanting forward, truncate 

 and slightly emarginate at tip, and about 4 mm. long and 2 J mm. 



