16 Transactions South African Philosophical Society, [vol. xir. 



is produced by the friction of the abdomen against the inner edge of 

 the elytra. 



Sexual Characters. — The sexual outer characters are very strongly 

 marked in some of the sub-families. They consist in cephalic and 

 prothoracic horns, tubercles or excavations, especially in many of the 

 CoprincE, GcotrupincE, Oiphnince, Dynastincz and a small number of 

 CetonincB ; in the other groups the difference is to be found in the 

 shape of the clypeus, the antennal club, the claws, &c., sometimes 

 the two sexes are alike. Although the enormously developed horns 

 on the head and prothorax of some of the males might prove to be 

 weapons of offence, dangerous even to armour-clad insects as some 

 of these are, I am not aware that they have been observed using 

 them in fight ; but I have two examples of Heliocopris gigas, w^hich 

 were found dead on the veld, having their cephalic horns inter- 

 locked ; one had turned over in the struggle, and both in death 

 retained this position. It is worthy of note that together with 

 males, in w^hich the sexual characters are exaggerated, are found 

 others, in which these scarcely differ from those of the females ; 

 or, in others again, having the distinctive characters considerably 

 less conspicuous than in the large development ; with this difference 

 there is a corresponding diminution in general size. ; 



Habits and Mode of Life. — Some Scarab^id^ feed on excre- 

 ments, decomposed animal and vegetable matter, many on roots, 

 others on leaves of trees or shrubs ; some prefer the nectar of 

 flowers or the juices, or sap exuding from trees and creepers ; 

 some are suspected of parasitism or commensalism, and the larvae 

 of some Dynastince and CetonincB are now known to feed on the 

 material of which termite mounds are made. The habits of the 

 South African species are mentioned, when known, with the descrip- 

 tion of genera and species. 



The Scarabaeid fauna in South Africa. — The former abundance 

 of big game, now replaced by cattle, has naturally made its influence 

 felt in South Africa, and the Copein^ are especially numerous. 

 Most of the genera are, however, represented elsewhere, and many 

 species are very closely allied to those occurring in the Eastern part 

 of Africa as far as Abyssinia, and even in Senegambia ; some are 

 even identical. 



In the Scarabcsini, however, there are six genera (Pacliysoma, 

 Sceliagcs, Circellium, Sphengcecits, Odontoloma, Gyronotus), which 

 are restricted to South Africa ; and Circelliuin is even restricted to 

 the South-Western Districts of the Cape Colony ; while in the 

 Coprini, Epirhinus, Macroderes, Dcloplcurus, Hcteroclitopits, and 

 Parapinotus are peculiar to South Africa, where also the species 



