INTRODUCTORY PAPERS ON LEPIDOPTERA, 147 



the great central ranges by the Glacial period, subsequent to 

 which it has gradually returned, chiefly froui Asia. The four 

 subregions admitted by Wallace are : — I. Central and North- 

 European, south to the central ranges, and, east to the 

 Caspian, and the valley of the Irtish ; 2. Mediterranean, south 

 to the Sahara, and east to the frontiers of India; 3. Siberian, 

 including all northern Asia, south to Turkestan, Thibet, the 

 desert of Gobi, and theAu)oor; 4. Mantchurian, including 

 Japan, and the country east of Gobi, and south of the Amoor, 

 as far as the Nanlin mountains, south of the Yang-tse-kiaug. 

 The latter district is interesting, on account of the mixture 

 of East Indian and North American forms which there 

 mingle with ordinary European species. Many groups ex- 

 tend much farther north in the east of Asia than in the west, 

 owing to the different conformation of the country. The 

 launa of Central Asia is comparatively little known at 

 present, and many insects far from uncommon in their own 

 localities fetch very high prices ; while others, occurring in 

 localities very rarely visited, and almost inaccessible to 

 Europeans, are absolutely unattainable. Besides the large 

 general works on the European Fauna by Esper, Hlibner, 

 Ochsenheimer and Treitschke, and Herrich-Schaffer, the 

 principal works on the Lepidoptera of the Palaearctic region 

 (not already mentioned, or confined to British species) are 

 those by Wallengren (for Sweden), Rauibur (for Andalusia), 

 Snellen (for Holland), Dubois (for Belgiuu)), Eversmann 

 (lor South Russia), Lucas andOberthur(for Algeria), Erschoff' 

 ((or Turkestan), and Menetries and Bremer (for the Amoor). 

 Local lists of the Lepidoplera of almost every country, 

 and many small districts in Europe have been published 

 either separately or in magazines. 



II. Ethiopian Region. — This includes Africa, south of 

 the Sahara, and the southern portion of Arabia. Wallace 

 divides it into subregions as follows: — I. East African, and 

 Central ; 2. West African ; 3. South African ; 4. Malagasy. 

 The first is by far the largest, the second taking from it 

 only a broad strip of the west coast, between the rivers 

 Gambia and Congo. 'J'he South African region extends on 

 the west coast north to Welwitsch Bay, and on the east to 

 Mozambique. The fourth includes Madagascar and the 

 adjacent islands, which have a peculiar fauna of their own. 



