THE TRIBE OF THE ANGLE-WINGS 159 



The Green Comma 



Polygonia f annus 



The Angle-wings exhibit interesting variations in the 

 geographical distribution of the species. Some are 

 characteristic members of the Canadian fauna, others of 

 the Alleghanian fauna. Some of those which are char- 

 acteristic of the former are scattered south well into the 

 latter, but the Green Comma is distinctively a northern 

 species — ^being found abundantly in the great regions 

 traversed by the trappers of the Hudson Bay Company 

 and occurring south as far as northern New England, being 

 very rare as far south as northern Massachusetts. It is 

 abundant on the higher slopes of the White Mountains. 



As one might expect from the short seasons of the far 

 northern regions in wliich this butterfly lives, there is only 

 one brood each year. In consequence the adult butterflies 

 live a long time. Coming from the chrysalis generally 

 the first weeks in August, they remain upon the wing a 

 month or more before they go into hibernation. They 

 come from their winter quarters in May and commonly 

 continue alive until late in June. Thus it is evident that 

 many of these butterflies must live at least ten months as 

 adults, an extraordinary longevity for one of these frail 

 creatures. 



The caterpillars are known to feed upon the foliage of 

 several kinds of plants. These include alder, currant, 

 gooseberry, willow, and black birch, the last two named ap- 

 parently being those most often chosen. 



Mr. S. H. Scudder called attention to the fact that these 

 butterflies are able to make a slight chcking noise as they 



