40 
SOUTH-AFEICA]Sr BUTTERFLIES. 
their bodies and wings began to be elongated and tlieir flight cliarac- 
teristically weakened. It would be at this stage," writes Mr. Wallace, 
that some of the weaker-flying Pieridse, which happened to resemble 
some of the Danaid^ around them in their yellow and dusky tints and 
in the general outline of their wings, would be sometimes mistaken for 
them by the common enemy, and would thus gain an advantage in the 
struggle for existence. Admitting this one step to be made, and all 
the rest must inevitably follow from simple variation and survival of 
the fittest." 
7. South-African Butterflies. 
As has been remarked above, the Extra-Tropical South- African 
Sub-Kegion possesses representatives of all the African or Ethiopian 
Families and Sub-Families except the Nemeobiinm^ a Sub-Family of 
ErycinidcG ; but the representation of this Sub-Family in the Eegion 
is exceedingly poor, only four species of one genus (Ahisara) being 
recorded. The Butterflies known to occur in the Sub-Region and those 
peculiar to it are numerically as follows, viz. : — 
Inhabiting Peculiar to 
South Africa. South Africa. 
Families . . . 5 . . . None 
Sub-Families . . 7 . . . None 
Genera . . . 69 . . . 6 
Species . . . 380 . . . 195 
Though the proportion of peculiar genera is thus little more than 
one-twelfth of the entire number represented, it should be noted that 
no fewer than twenty-one other genera — making twenty-seven in all, 
or rather over two-fifths — are confined to the African Region. Simi- 
larly, while but slightly above half the species appear to be endemic, 
yet only thirteen,-^ or about one-twenty-ninth, are known to extend 
beyond the Region. 
The genera which are not known to extend into Tropical Africa are the 
following, viz., two in the Family Nymphaliclm (Sub-Family Satyrince), — 
Meneris (one species) and Cmnyra (one species) ; and four in the Family 
LyccBiiidcv^ — Capys (one species), Arrugia (three species), D'Urlania 
(three species), and Deloneura (one species). 
There are seventeen Tropical- African genera besides Ahisara, of 
which no South- African representatives are known, viz., (Satyrinm) 
Bicychis, Heteropsis ; (Nymphalince) Imra, Mymnias, BiscopJwra, Bole- 
schallia, Ergolis, Enotrea, Cyrestis, Aterica, and Philognoma ; ^ (^Lycmn-- 
idee) Phytala, E;pitola, Miletus, and Hewitsonia ; and {Hes'peridoe) Cera- 
trichia and Carystus. The rich Tropical genera Euryphene, Euplixdra^ 
^ These are Danais Chrysippus, Atella Phalantha, Pyrameis Cardui, Hypanis Ilithyiat 
Diadema Misippus, Melanitis Leda, YptJiima Asterope, Lyccena Bcetica, Z. Lysimon, L* 
Trochilus, Terias Hecahe, Pieris Mesentina, and Teracolus Eris. 
2 VaraneSt Cram., seems properly referable to Charaxes. 
