4 THE ENTOMOLOGIST. 



terminates respectively in the south alps, the north alps, and 

 Central Germany, at the heights of about 4500, 4000, and 3000 

 feet, and is the highest limit at which the oak, beech, and birch 

 trees will flourish. 



3. Tlie Lon-er Alpine zone. This is the great region of 

 coniferous trees, and runs up to the height of 6000, 5500, and 

 4500 feet in the three mountain districts mentioned above. In 

 Norway it terminates at the height of from 700 to 3000 feet, 

 according to the latitude. 



4. Tlie Upper Alpine zone. This belt extends above the pine 

 trees to the additional height of 1500 feet, and is the region of 

 the rhododendron, great tracts of which occur in the Swiss alps, 

 making this part of the mountains quite bright with their 

 millions of blossoms in the summer time. In Scandinavia this 

 belt is very vaguely represented, the width being often reduced 

 to very trivial dimensions. 



5. The Snoiv zone. In this zone only small alpine plants 

 and lichens flourish, and it extends up to where the first great 

 patches of the everlasting snow are encountered, which is some- 

 times several hundreds of feet beyond the theoretical line of 

 congelation. 



Now, in deciding the limitations of the zones in the British 

 Isles, I have been guided largely by the preceding plan, and 

 have, as far as possible, given the exact British equivalents for 

 each of them. My proposed list is therefore as under : — 



1. Tlie South Coast zone. This belt coincides with the lower 

 portion of Speyers' lowland zone, and corresponds to the limit in 

 Europe to which the grape-vine will flourish, which terminates 

 polewards at the annual isotherm of 50° F., or at about latitude 

 50° on the Continent. In the British Isles it includes all the 

 southern coasts of England and Wales, from the neighbourhood 

 of Liverpool in the west to Harwich in the east, as well as all the 

 southern portions of Ireland. Its southern limits are in the Scilly 

 Islands, which possess a mean annual temperature of 53° F., and 

 it includes the whole of the south coast up to the average height 

 of about 300 feet above the sea-level. It constitutes the northern 

 limit of the Clematis ritalba. Several Austral species of Lepi- 

 doptera are found exclusively in this region ; but the only species 

 of butterfly which can be said to belong to it alone is the little 

 Lulworth " skipper" {Hesperia actceon). 1 think it is necessary 

 to provide this zone, as an unfair value would, if it was omitted, 

 be attached to the one which immediately follows in the order of 

 ascending, and with which it would otherwise be incorporated. 



2. The Lower Hill zone corresponds to the remaining half of 

 Messrs. Speyers' lowland zone, and terminates in this country at 

 the annual isotherm of 45° F. It constitutes by far the most 

 extensive belt in the British Isles, embracing the greater part of 

 the country within a moderate vertical distance of the sea-level, 



