582 THE BUTTERFLIES OF XEW ENGLAXD. 



ate zone above Latitude 60% but also the contiguous arctic* and subarctic 

 regions and even that portion of South America which lies south of Latitude 

 35"; i.e., beyond the limits of continental extension in the Old AVorld. 

 In the north temperate regions few of the species reach the southern limits 

 attained by most of the species of Argynnis, and of these few, a number 

 are confined to elevated districts ; for Brenthis has its centre of develop- 

 ment on the northern confines of the temperate zone. Several of the 

 species are sitpposed to be common to both hemispheres, but such are 

 wholly restricted to the subarctic or arctic regions. Apart from these, 

 the genus is less richly represented in the New than in the Old World. 

 Three species only are found in eastern North America south of the St. 

 Lawrence ; two occur in nearly equal abundance throughout New England, 

 while the third is limited to the subalpine regions of its northern moun- 

 tainous district. 



General appearance. The butterflies are rather below the medium 

 size ; their wings closely resemble those of Argynnis in the design and 

 coloration of the upper surface, but within the mesial band of the hind 

 wings, the base is traversed by a net work of many irregular markings : 

 the under surface of the latter not only differs from the pattern of Argyn- 

 nis, but also shows great diversity among the species, as may be seen by 

 a comparison of those described below. The groiuid color is reddish 

 brown, traversed by a broad, somewhat irregular, black edged, intra-me- 

 sial band, usually bent in the middle, and either simply paler than the 

 ground color or silvery, or in places (especially near the middle and next 

 the costal and inner borders ) dashed with white or silver ; there are a few 

 pale or silvery basal spots, while in the middle of the outer half of the 

 wing the maculations of the upper surface are repeated and sometimes 

 preceded by an interrupted pale or silvery band : there is a submarginal 

 series of dark lunules, sometimes followed exteriorly by white or silvery 

 spots. 



Life history. The insects of this genus, which ally themselves to the 

 Melitaeidi in many ways and appear to borrow from them a tendency to 

 lethargy while in the caterpillar stage, seem to present among themselves 

 greater diflerences in habit than occur in any other similar group of but- 

 terflies, the central European species differing considerably from those of 

 the United States, though all the known species, whether European or 

 American, winter as only partly grown caterpillars. The European but- 

 terflies are single-brooded in the cooler parts of their range, and double 

 in the warmer, the second brood always being much weaker in numbers. 

 Their history was first traced, more than sixty years ago, by a French nat- 

 uralist, whose statements have since been neither verified nor contradicted, 



*. Two or three species have been obtained have Ijeen collected, namely between Lati- 

 f roni the highest latitudes at which insects tude 81° 30 and 82° N. 



