ARCTIC BUTTERFLIES CLARK 271 



varying intensity, with fogs and mists and drizzling rains or flurries 

 of snow occur almost continuously. A damp, raw, and chilly day with 

 a light breeze in early spring is a fair sample of the pleasantest Aleu- 

 tian summer weather. Here there are no trees, and only a few small 

 bushes in protected situations. But wherever soil occurs there is luxu- 

 riant vegetation, and many lovely flowers, especially lupines and 

 anemones. In spite of the lovely flowers and the numerous and inter- 

 esting birds I still remember the Aleutian Islands as the most forlorn 

 region I have ever visited. No butterflies live in this depressing chain 

 of islands. The climate, though not cold, is too stormy and too wet 

 for them. The Pribilof Islands, north of the Aleutians, also have 

 no butterflies, and only seven kinds of moths. 



The Aleutians and the Pribilofs have their counterparts in the 

 Southern Hemisphere. To the eastward and somewhat north of 

 Tierra del Fuego lies the archipelago of about 200 islands known as 

 the Falkland Islands. Here the temperature is very equable, the aver- 

 age for the two midsummer months being about 47° and that for the 

 two midwinter months about 37°. The sky is almost continuously 

 overcast, and rain falls, mostly as a drizzle and in frequent showers, 

 on about 250 days during the year. The rainfall is not great, being 

 only about 20 inches, but the mean humidity for the year is 80. Owing 

 to the absence of sunshine and of summer heat, wheat will not ripen, 

 barley and oats can scarcely be said to do so, the common vegetables 

 will not produce seed, and no trees will grow. The sole butterfly of 

 the Falkland Islands is a little fritillary {Brenthis cytheris falk- 

 landica (pi. 3, figs. 21, 22)) that has recently been described. 



Far to the eastward of the Falkland Islands and slightly farther 

 north there lies, southeast of Africa, the large island called Kerguelen. 

 Here the lowest temperature in winter is seldom less than 32°, and 

 the summer temperature occasionally approaches 70°. But Kerguelen 

 lies within the belt of rain at all seasons of the year and is reached 

 by no drying winds. It has no trees, but on the lower mountain slopes 

 there is much rank vegetation that is saturated with moisture con- 

 stantly. There are no butterflies. The Lepidoptera are represented 

 by a single kind of short-winged flightless moth, of which the cater- 

 pillars feed on the curious plant called the Kerguelen cabbage. Both 

 butterflies and moths are absent from all the other islands in the 

 Antarctic seas and from the Antarctic continent. 



From this we see that the severest cold of the far northern regions 

 can be withstood by certain kinds of butterflies. They will thrive in 

 the most rigorous of climates, if only there is sufficient sunlight and 

 sufficient food. But in wet and stormy regions, though the tempera- 

 ture may be relatively mild and equable, they are unuble to exist. 



