LEPIDOPTERA 



273 



the presence of a whitish spot on both fore and hind wings, near the 

 apex, and between two larger black patches. On the lower surface of the 

 hind wings there is a small re- 

 shaped silvery bar. This species 

 occurs throughout Canada and 

 the northern portion of the 

 United States east of the Rocky 

 Mountains. It is double- 

 brooded. 



Polygdnia. — The butterflies 

 of this genus resemble the pre- 

 ceding species in having a me- 

 tallic spot on the lower surface 

 of the hind wings, but differ in 

 having the inner margin of the 

 fore wings roundly notched 

 beyond the middle. f IG - 472 ' ~ **"**»»««■• 



Ten species occur in this country. These differ principally in the 

 coloring and markings of the under surface of the hind wings. The fol- 

 lowing are some of the more common ones. 



The green comma, Polygdnia faunus. — The silvery mark of the hind 

 wings is usually in the form of a C or a G, the ends being more or less 

 expanded (Fig. 471, 2) but sometimes it is reduced to the form of an L. 

 The lower surface of the wings is more greatly variegated than in any 

 other species of this genus; and there is a larger amount of green on this 

 surface than in any other of the eastern species, there being two nearly 

 complete rows of green spots on the outer third of each wing. 



The larva feeds upon black birch, willow, currant, and wild goose- 

 berry. This is a Canadian species; but it is also found in the mountains 

 of New England and of New York, and in the northern portions of the 

 western states, extending as far south as Iowa. It is single-brooded. 



The hop-merchant, Polygdnia comma. — As in the preceding species, 

 the silvery mark of the hind wings is in the form of a C or a G (Fig. 

 471, 3) but the general color of the lower surface of the hind wings is 

 very different, being marbled with light and dark brown; and the green 

 spots so characteristic of faunus are represented here by a few lilaceous 

 scales on a submarginal row of black spots. 



Two forms of this species occur. In one P. comma dryas, the hind 

 wings above are suffused with black on the outer half, so that the sub- 

 marginal row of fulvous spots is obscured, and on the lower side the 

 wings are more yellowish than in the other form. The latter is the 

 typical form of P. comma comma. 



The larva feeds upon hop, elm, nettle, and false-nettle. It is often 

 abundant in hop-yards, and the chrysalids are commonly known as hop- 

 merchants, from a saying that the golden or silvery color of the metallic 

 spots on the back of the chrysalis indicates whether the price of hops is 

 to be high or low. This species is found in Canada and the northern 

 part of the eastern half of the United States; its range extends south to 

 North Carolina, Tennessee, Arkansas, and Oklahoma. It is double-brooded 

 in the North, and at least three-brooded in the South. 



The violet tip, Polygdnia interrogations. — This butterfly (Fig. 471, 

 8) is somewhat larger than the preceding species of Polygonia and differs 



