196 RHOPALOCEEA AFBICJE AUSTBALIS. 



lower being the larger. In one $ , the fulvous indistinctly extends round 

 outer edge of large ocellus, as in Cramer's figure, and indications of this 

 appear in others. 



Local. Mountains and hill-sides, and sandy plains. 



October (e), and December. 



This dark and peculiar-looking insect approaches more nearly to Clytus t 

 Linn., than to any other South African Satyrian. When only acquainted 

 with a few faded $ specimens, I felt fully inclined to think, with Mr. 

 Westwood, that Cassus might well be an extreme variety of the variable 

 Clytus; but since having taken $ s, and observed the insect for two seasons 

 in its native haunts, I am quite convinced of its being a distinct species. In 

 structure the two species are almost identical, but Cassus is rather more 

 robust, and has rather longer antennas, with more rounded, abruptly-formed, 

 and flatly-shaped clubs. Specimens found on the sandy flats are invariably 

 much smaller and darker than those inhabiting tbe hills, the markings of 

 some $ s being all but obliterated, so that the surface is almost unicolorous. 

 The ochreous colouring of the under-side, too, is wanting in the lowland 

 examples, being represented by irregular greyish scaling, conspicuous on the 

 dark ground. Cassus is at once distinguished on the wing by its dark hue. 

 I have not noticed it before the end of October, or after the middle of 

 December, while Clytus does not appear before the middle of February, and 

 remains out till the middle or end of May. Among the great number of 

 examples of Clytus that I have examined, I have never noticed one with 

 more than a single ocellus in fore-wing. Cassus seems confined to the 

 Western Province of the Colony. 



Cape Town. Stellenbosch. Coll. Tri. et Coll. S. A. 

 Mus. 



Cape of Good Hope. Coll. Brit. Mus. 



Genus EREBIA. 



Erebia, Dalman, Boisd. 



Satyrus (pars), Boisd. 



Pseudonympha and Physcseneura, Wallgr. 



IMAGO. Head : eyes smooth ; palpi long, densely hairy, 

 slightly ascendant ; antenna short, with an usually rather 

 gradually-formed, but in E. Hippia and Sabacus abrupt, 

 club. Fore-wing : costa moderately arched ; apex rounded ; 

 hind-margin entire, nearly straight ; costal nervure often 

 swollen at base. Hind-wing : inner-margins touching natu- 

 rally for nearly half their length, forming a very shallow, 

 imperfect groove, and thence rather markedly divergent ; 

 hind-margin entire, or very slightly dentate. 



The typical group of Erebia is very numerously represented 

 in Europe, the number of species being greater than in any 

 other European genus, with the exception of Lyccena 

 (Polyommatus). Nearly all of these insects are found 

 exclusively in mountainous districts. 



The seven South African species of this genus all have the 

 costal nervure of fore-wing markedly enlarged at base, but 



