406 THE STUDY OF INSECTS. 



ro-ga-ti-o'nis). This butterfly (Plate VI, Fig. 8) is some- 

 what larger than the preceding species of Polygonia, and 

 differs in the form of the silvery mark, which consists of a 

 dot and a crescent, resembling somewhat an interrogation- 

 mark, but more nearly a semicolon. On the upper side the 

 outer margins of the wings and the tails of the hind wings 

 are tinged with violet. 



This species is dimorphic ; and the two forms differ so 

 constantly and in such a marked manner that they were 

 described as distinct species. In P. intcrrogationis fabricii 

 (P. i. fa-bric'i-i) the upper surface of the hind wings is not much 

 darker than that of the fore wings, and there is a submarginal 

 row of fulvous spots in the broad ferruginous brown border. 

 In P. interrogalionis nvibrosa (P. i. um-bro'sa) the outer two 

 thirds of the upper surface of the hind wings is blackish, and 

 the submarginal fulvous spots are obliterated, except some- 

 times faint traces near the costal margin. 



This species is found in Canada and throughout the 

 United States east of the Rocky Mountains. 



IV. The Sovereigns. These butterflies differ from other 

 Nymphalinae in having the club of the antennae marked by 

 four slightly elevated lines, and in that veins I, II, and III 

 of the hind wing (Fig. 467, p. 395) separate at the same 

 point. This group includes some of our most elegant but- 

 terflies ; the larvae are grotesque in appearance, being very 

 irregular in form and strikingly mottled or spotted. 



The Banded Purple, BasilarcJiia artlieinis (Bas-i-lar'chi-a 

 ar'therjnis). The upper surface of the wings is velvety 

 chocolate-black, marked with a conspicuous white bow 



(Fig. 478)- 



This is a Canadian species which extends a short distance 

 into the northern part of the United States ; the larva feeds 

 on birch, willow, poplar, and many other plants. 



The Red Spotted Purple, BasilarcJiia astyanax (B. 

 as-ty'a-nax). The upper surface of the wings is velvety 

 indigo-black, tinged with blue or green. There are three 



