LEPIDOPTERA 763 



This is a Southern form, which extends into the southern portions 

 of New England, New York, Michigan, Wisconsin, Iowa, and Ne- 

 braska; and into the northern portions of TlHnois, Indiana, and Ohio. 



(2) The dull-eyed grayling, Cercyonis alope nephele. — In this form 

 the yellow band of the fore wings is either absent or represented by 

 a faint pallid cloud. In other respects it closely resembles the blue- 

 eyed grayling. 



This is a Northern form; the southern limits of its range overlap 

 the northern limits of the range of the blue-eyed grayling as given 

 above. 



(3) The hybrid gra^dings. — In that narrow belt where the ranges 

 of the two forms of Cercyonis alope described above overlap, all 

 variations between the two types occur. In most of these intergrades 

 the eye-spots of the upper side of the fore wings are surrounded by 

 yellowish rings, or each of them is on a yellowish patch. 



(4) The sea-coast grayling, Cercyonis alope maritima. — In a nar- 

 row belt along the Atlantic coast there occurs a form which is smaller 

 than those described above, and of a dark color; this form is easily 

 recognized by the color of the band bearing the eye-spots, it being 

 reddish }'ellow. 



The White Mountain butterfly, CEneis semtdea. — The genus GEneis 

 is composed of cold-loving arctic species whose natural habitat is the 

 Far North; but some members of this genus are found within the 

 limits of the United States. Their presence h ere and their distribution 

 are extremely interesting. The best -known of these forms is the White 

 Mountain butterfly. 



This butterfly is found only on the higher parts (above 5,000 feet) 

 of the White Mountains in New Hampshire, and on the highest peaks 

 of the Rocky Mountains of Colorado, above 12,000 feet. 



These two widely separated colonies of this butterfly are believed 

 to be the remnants of an arctic fauna which was forced southward 

 during the Ice Age. At the close of this period, as the arctic animals 

 followed the retreating ice northward, the tops of these mountains 

 became colonized by the cold-loving forms. Here they found a 

 congenial resting place, while the main body of their congeners, which 

 occupied the intervening region, was driven northward by the increas- 

 ing heat of the lower land. Here they remain, clinging to these 

 islands of cold projecting above the fatal sea of warmth that fills the 

 valleys below. 



The White Mountain butterfly is a delicate-winged species. The 

 upper surface of the wings is grayish brown, without spots, except 

 sometimes a minute one in cell Mi of the fore wings; the fringe of 

 the wings is brownish white interrupted with blackish brown at the 

 ends of the veins. On the hind wings the marbling of the lower surface 

 shows through som.ewhat. On the lower surface, the tip of the fore 

 wings and the greater part of the hind wings are beautifully marbled 

 with blackish brown and grayish white. The expanse of the wings is 

 43 mm. 



