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. interrogation^ 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. interrogationis umbrosa (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 antennas 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, Basilarchia arthemis (Bas-i-lar'chi-a 
ar'the-mis).—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, Basilarchia astyanax (B, 
as-ty'a-nax).—The upper surface of the wings is velvety 
indigo-black, tinged with blue or green. There are three 
