248 THE ENTOMOLOGIST. 



which had formerly existed in this area were either all extirpated 

 or had been driven south to the edge of the ice-cap, where alone 

 their pabula could survive. At this period all the countries 

 bordering on the Mediterranean must have possessed a fauna 

 and flora somewhat similar to that which now reigns supreme in 

 Scandinavia at the present day. 



Upon milder climatic conditions ensuing the ice-cap, which 

 had previously enveloped Europe in its clutches like a gigantic 

 cuttle-fish, gradually receded, carrying in its trail those butter- 

 flies and their food-plants which had continued to survive upon 

 the southern edge of its area. Thus we find existing at the 

 present day in high latitudes, and also at considerable altitudes 

 upon mountains, where climatic conditions prevail parallel with 

 those which existed during the glacial period, the most ancient 

 forms of the various genera and species. These have in many 

 cases since branched out into numerous other forms, under more 

 favourable physical surroundings, in lower latitudes and at less 

 elevated altitudes. 



In the north, Scandinavia, Lapland, and Finland constitute 

 the happy hunting-grounds of those who wish to meet with these 

 ancestral forms ; while further south they may only be obtained 

 on the Alps and Pyrenees, and other mountain-ranges of Central 

 Europe which are of a sufficient vertical elevation, and furnish 

 zones with an equivalent vegetation to those now existing in 

 arctic and subarctic regions. 



When the major part of Europe was submerged beneath a sea 

 of snow and ice, other large portions of the palasarctic area were 

 left uncovered, at least were free from it in the summer time. 

 This consisted of land even further to the north than the 

 glaciated western continent, namely, in Siberia. The reason of 

 this is, as has been ably demonstrated by Prof. A. Pi. Wallace, 

 that in order to induce glaciated conditions a certain amount of 

 humidity must occur, whereas this was absent in the region in 

 question, as is evidenced by the non-presence of geological proof 

 to the contrary, such as ice-scratchings, &c. At the same time 

 the cold may have been much more intense in the winter, 

 although in the summer, the laud being free from snow, 

 vegetation could make its appearance, together with the 

 attendant butterflies. It is highly probable, therefore, that 

 many species of the latter were perpetuated and survived 

 within this area during the glacial period, which, upon more 

 favourable climatic conditions making their appearance in 

 Northern and Central Europe, spread westwards, and inter- 

 mingled with those which at the same time advanced north- 

 wards from the south. 



As the result of his investigations, Ernst Hoffmann asserts 

 that of the 290 species of Ehopalocera inhabiting our con- 

 tinent at the present time, no less than 173 were originally 



