274 



THE STUDY OF INSECTS 



in the form of the silvery mark, which consists of a dot and a crescent 

 resembling a semicolon. It received its scientific name from the Greek 

 note of interrogation, which is identical with our semicolon. On the 

 upper side, the outer margins of the wings and the tails of the hind wings 

 are tinged with violet, which fact suggested its common name. 



This species is dimorphic ; and the two forms differ so constantly and 

 in such marked manner that they were described as distinct species. In 

 P. interrogationis interrogationis 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. 

 interrogationis umbrosa the outer two-thirds of the upper surface of the 



hind wings is blackish, and the 

 submarginal fulvous spots are ob- 

 literated, except sometimes faint 

 traces near the costal margin. 



This species is found in Canada 

 and throughout the United States 

 east of the Rocky Mountains. 



THE SOVEREIGNS 



Fig. 473. — Wings of Basilarchia aslyanax. 



known species. 



The banded purple, Basil- 

 archia arthemis. — ■ The upper 

 surface of the wings is velvety 

 chocolate-black, marked with a 

 conspicuous white bow (Fig. 

 474)- 



This is a Canadian species 

 which extends a short distance 

 into the United States ; the larva 

 feeds on birch, willow, poplar, 

 and many other plants. 



The members of this group differ 

 from other Nymphalidae in that the 

 first three veins of the hind wings 

 separate at the same point (Fig. 

 473) ; in the other nymphs the hu- 

 meral vein arises beyond this point. 

 The club of the antennae is very 

 long, and increases in size so grad- 

 ually that it is difficult to determine 

 where it begins. In its thickest 

 parts it is hardly more than twice 

 as broad as the stalk. The palpi are 

 slender, and the wings are rounded. 



The larvae present a very gro- 

 tesque appearance, being very ir- 

 regular in form, and strongly 

 mottled or spotted in color. 



The following are our best- 



Fig. 474. — Basilarchia arthemis. 



