tlic (jenus Ercbia. 323 



namely, melampm, which occurs in Silesia, and epiphron 

 in Silesia and the Hartz Mountains ; whilst 3 others, 

 namely, medusa, (Ethiops, and lujea, are found not only 

 in the plains and lower hills of Central Germany, but 

 extend far east into Siberia and Amurland, where they 

 are the only European non-arctic species which occur. 



In South-eastern Europe and the Balkan Peninsula 

 we find no peculiar species except afra and melas, the 

 former a lowland or steppe, the latter a high-mountain 

 insect ; both of them extend into Western Asia. 



In the Caucasus we have no peculiar species at all, 

 and none of the Siberian or Turkestan species occur. 

 This is very remarkable when we consider the great 

 elevation, extent, and isolation of the Caucasian Moun- 

 tains, which would seem to be admirably adapted to the 

 habits of the genus. Either there is some geological or 

 other condition which has prevented the development of 

 high alpine species in the Caucasus, or else the higher 

 parts of the range have been greatly neglected by 

 entomologists, for in the Grand Duke Eomanoff 's Cata- 

 logue of the Butterflies of the Caucasus I find an almost 

 total absence of alpine butterflies peculiar to the range, 

 Paniassius nordmanni and Satyrus alpina being perhaps 

 the only exceptions ; whilst the high mountain species 

 of Central Europe are only represented by three or four, 

 namely, Pieris callidice, Ar^gynnis pales, Erehia tyndarus, 

 and a form of Lyccena orhitidus. As none of the alpine 

 forms found in Turkestan or the Himalayas extend so far 

 west, we have what seems to be a unique instance of a 

 great chain of high mountains almost devoid of true alpine 

 Lepidoptera. I see no means of accounting for this 

 but the extreme isolation of the range, which is bounded 

 on the east and west by sea, and on the north by a steppe 

 of more or less desert character and immense extent. 



In the whole of Europe, therefore, including arctic 

 species, we have 29 species of Ercbia, — about half the 

 genus, — of which only about 6, namely, medusa, ? me- 

 lanqnts, tyndarus, lappona, (dhiops, and ligca, extend to 

 Siberia, and one, E. afra, to Turkestan. 



In Turkestan and the Altai regions, but with two or 

 three exceptions confined to the mountain ranges, we 

 have another quite distinct group of species, about 14 in 

 number, of wdiich only tyndarus is found in Europe, and 

 none apparently in Eastern Siberia, the remainder 

 being, as far as we know, peculiar to the region. 



