590 THE BUTTERFLIES OF NEW EXriLAND. 



genial, until they renchecl the mountain peak, now bare of snow in the 

 short summer. Here, blown sidewise by the wind, they patiently cling to 

 the rocks ; or in clear weather, on weak and careful wing, they fly from 

 flower of stemless mountain-pink to blue-berry, swaying from their narrow- 

 tenure of the land. Drawn into the currents of air that sweep the moun- 

 tain's side, they are forced downwards, to be parched in the hot valleys 

 below. Yet they maintain themselves ; they are fighting it out on that 

 line" (Grote). 



It may here be remarked that botanists have not yet distinguished two 

 zones of life above the trees in our White Mountains, but only between 

 those plants that are found exclusively in that region or in the high north, 

 and those which, while found there in greatest abundance, are also found 

 decidedly out of it. But my own casual observation of the comparative 

 abundance of certain flowers over the districts I have distinguished as 

 upper alpine and lower alpine, leads me to believe that a careful survey of 

 the field would bring one to the same conclusion as I have drawn in the 

 case of the butterflies. Moreover, Agassiz noted many years ago certain 

 distinctions, as the following extract from his "Lake Superior" shows: 

 "Above this level the mountain is naked, and many fine plants make their 

 appearance which remind us of the flora of Greenland, and many of which 

 grow on the northern shores of Lake Superior, such as Arenaria groen- 

 iandica, Vaccinium caespitosum, uliginosum, etc. The summit of the 

 mountain, at the height of six thousand two hundred and eighty feet, pro- 

 duces several plants which have no representatives south of Labrador. 

 Such are Andromeda [Cassiope] hypnoides, Saxifraga rivularis. Rhodo- 

 dendron lapponicum, Diapensia lapponica." (p. 186). The phenoga- 

 mous vegetation of the whole district is indeed pretty well known, but it 

 would be well to prepare full catalogues of the plants found in every dis- 

 tinct centre of alpine vegetation, with their comparative abundance at 

 each place. Thus in the immediate vicinity of Mount Washington we 

 should have separate comparative lists of plants of the elcA'ated plateaus, 

 of the borders of the Lakes of the Clouds, the base of the soutlierly cliflP 

 of Mount Munroe, the boggy area above the Fall of the Thousand 

 Streams, the neighborhood of the snow field in Tuckerman's Ravine, the 

 Alpine Garden, etc., with special notes upon the heights at which they 

 are found as nearly exact as possible. The study, too, of the other in- 

 sects of this region is just as instructive as is that of the butterflies or the 

 plants. Thus among the moths of the genus Agrotis alone, Mr. Grote 

 finds no less than three species, imperita, islandica and carnea, which 

 occur, besides on these lofty summits, only in Labrador and in Lapland or 

 Iceland, while a considerable number of other moths and of Coleo])tera 

 are also known, inhabitants otherwise only of the high north. 



It will naturally be asked how it is possiljle that insects, and especially 



