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GENERAL NOTES. 373
the west of Scotland, but in England, and many of them near
London.] The strongest-flying genera are usually the most
widely distributed. The great areas of distribution are therefore
not sharply defined, and it is an error to take the distribution
of the very limited European fauna as the groundwork of a
system applicable to the whole world. Most of the polar species,
and those of Europe generally, occur throughout Central and
northern Asia, while the Mediterranean fauna extends from the
Canaries through North Africa and Southern Europe some distance
into Western Asia. The great chains of mountains extending
more or less continuously from the Caucasus to the
Pyrenees form the boundary of the Mediterranean fauna on
the north, and interfere more with the wider spread of species
than either the Atlantic [?] or the Mediterranean.
2. Africa, the region of the genera Anthocharis [Callosune],
Acreea, Char axes, and Romaleosoma. The whole of the northern
part of Africa belongs to the European fauna; and Africa may
on the whole be regarded as a second section of it. The whole
of North Africa, except the Mediterranean fauna, on this side
the Atlas is very poor in Lepidoptera, compared with the opposite
European coasts, in consequence of the want of great forests,
and the marshy nature of much of the flat country. Other
causes are the heat and dryness of the summer, the burning of
the vegetation by the inhabitants, &c. On the whole, the Lepidopterous
fauna of Africa is very small for the size of the continent,
owing to the great expanse of territory covered by rainless
deserts. Several Indian species occur on the coasts of the Red
Sea. The principal African genera of Rhopalocera are then
enumerated, and the number of species occurring in Africa and
the other quarters of the globe compared. The following genera
are noticed as very poorly represented in Africa :—Euplaza,
Danais, Thecla, and Hesperia. [No true Thecla occurs in Africa
south of the Sahara ; but Africa possesses several characteristic
genera of Lyccenidcs.]
3. The South-Asiatic or Indian fauna: Asia, the district of
the genera Ornithoptera, Danais, Euplcea, Limenitis, Adolias,
Diadema, and Parnassius. This fauna extends over a still wider
range than the European, and may be regarded as the original
stem of the entire Old-World fauna. It extends from the mountains
of Central Asia, throughout India, China, a great part of
Australia, and the Pacific Islands. Westward it extends to
Arabia and Syria, where it touches the European fauna.
4. Australia and Polynesia : the region of the genera Antipodites,
Agarista, Hecatesia, Synemon,. Tear a, Opsirhina, and Oiketicus.
This fauna has without doubt been derived from the
Indian by migration, insects being conveyed from one district to
another across the sea by the monsoons. The species would then
become rapidly modified by the influence of climate. Nothing