Rhopalocerous forms in South Africa. 267 



the eastern districts; (3) tlie flora of the northern inland 

 districts; and (4) the immigrant sub-tropical coast flora. 

 All these divisions intrude on each other, and since the 

 republication of Harvey's " Genera " many plants noted 

 there as Avestern have been found to extend into the east, 

 while in like manner many noted as Natalian are found 

 far to the southward of Kafirland proper, between the 

 motmtain chain and the seaboard. 



Another rough division, made generally by the farming 

 population, is important as affecting insect life. The 

 coast land and the mountain tops consist principally of 

 what is known as the sour grass veld (the grasses abound- 

 ing in woody fibre and somewhat innutritions); interme- 

 diate between this and the siveet karroo or bush veld 

 (characterized by a dwarf scrub scarce in grasses) is the 

 gehrokte or sweet grass veld, in which dwarf bushes and 

 grasses are very equally intermixed. This latter is charac- 

 terized by no definite district, occupying sometimes parts 

 adjoining the coast and sometimes parts inland ; in the 

 one instance being visited by a slightly more and in the 

 other by a slightly less abundant rainfall than the adjoin- 

 ing coimtry. Thus plants and insects allied to those 

 chiefly peculiar to the seaboard arej, occasioially to be 

 found inland, as it were on little islands or broken pro- 

 montories, and generally in the neighbourhood of some 

 spur of the moimtain ranges. I have no doubt that in 

 wet seasons with southerly winds these localities are often 

 peopled by migrants from the seaboard, as at such times 

 I have noticed birds and insects migrating — seabirds 

 being bloAvn far inland. 



These general statements cannot be as yet thoroughly 

 demonstrated, but it is curious to note how on the sea- 

 board plants may be found in the river valleys either of 

 the same species or of forms allied to those of the inner 

 districts, while they are completely absent in the higher 

 ground adjoining, the plants of which may be described 

 as sub-tropical. Sometimes these differences are so slight 

 as to be only distinguishable Ijy a more luxuriant growth 

 or by the different texture and fla\'our of the foliage — a 

 difference sufficient to render them distasteful and noxious 

 to domesticated animals. Portulacaria Afra (Spckboora) 

 and some species o^ Euclece, gTcedily devoured in the drier 

 districts inland, appear even in dry seasons com})aratively 

 distasteful to sheep on the coast. The introduced prickly 

 pear {Opuntia vulgaris), which forms large thickets in 



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