164 
SOUTH-AFRICAN BUTTERFLIES. 
usually about midway between forking of third and fourth nervules 
and extremity of cell, but sometimes much nearer the latter ; upper 
disco-cellular nervule very short, slightly oblique, sometimes a little 
curved, — lower one long, arched, occasionally angulated ; discoidal j 
cell short, less than half length of wing, moderately wide, truncate at | 
extremity. Hind-ioings rather bluntly sub-ovate ; costa moderately j 
arched ; anal angle rather pronounced ; convex inner-margins forming 
a groove covering three-fourths of abdomen ; first subcostal nervule 
arched, given olf some distance before extremity of cell ; upper disco- 1 
cellular nervule of moderate length, straight, oblique, — lower one con- 
siderably longer, angulated above its middle point ; internal nervure 
rather long, ending at some distance beyond middle ; $ (in the Edusa 
group) with an elongate-ovate patch or badge of small, closely-set, 
elevated scales near base, just above subcostal nervure. Legs rather 
short and stout, scaly ; femora with long and rather sparse hair be- 
neath ; middle and hind tibiae finely and sparsely spinulose beneath, 
their terminal spurs of moderate size ; tarsi finely spinulose generally, 
their claws very deeply bifid, without paronychia. 
Abdomen rather short, compressed but not very slender. 
This very compact and well-defined genus (of which the well- 
known " Clouded Yellows " of Europe are typical) consists of a limited 
number — variously estimated at from twenty-six to forty- eight — of 
species, very closely allied, and mainly characteristic firstly of the 
Palsearctic, and secondly of the Nearctic Regions. Several species are 
circumpolar in the Northern Hemisphere, and the majority is in tem- 
perate regions limited to high alpine tracts. It seems most probable 
that Colias is one of the groups which was of very wide and general 
prevalence during the last glacial period, but has since in tropical 
regions been compelled to retreat to the mountains. Though extend- 
ing all through America, from the extreme north (Grinnel Land) to 
Cape Horn, it is confined to the Andes in the great tropical belt ; and 
in the Oriental Region only appears on the Himalayan boundary, with 
the exception of an isolated species on the Nilghiris in Southern India. 
Tropical Western Africa has yielded no representative of the genus, 
but South Africa has one exceedingly common and generally distri- 
buted species {Eledra, Linn.), a very close ally of the European Edusa. 
The latter is abundant on the African shores of the Mediterranean, 
and Electra is recorded by M. Oberthtir as having occurred in Shoa on 
the Abyssinian plateau, while Mr. Godman has noted the occurrence of 
a Colias (referred by him to Edusa) among Mr. Johnston's captures on 
Kilima-njaro. 
These butterflies are orange, orange-yellow, sulphur-yellow, or 
yellowish-white above, with a more or less developed blackish border, 
a black terminal disco-cellular spot in the fore-wings, and a larger 
orange one in the hind-wings ; beneath, they are of a paler yellow, 
always more or less tinged with green ; their antennsD and legs and 
