PIERIS. , • 319 



rate, and those of oleracea more triangular ; the outer half of the 

 costal border of the secondaries is slightly more docked in frigida 

 than in oleracea; the dark narrow line which follows the costal 

 border of the primaries extends around over rather more than half 

 the outer border of the wing, while in oleracea it seldom extends 

 beyond the tip, and very rarely half way round the outer border ; 

 the nervures on the under surface are more heavily marked than 

 in the darkest individuals of oleracea, though the markings are in 

 the same locality, such as the outer and uppermost nervules of the 

 primaries, the median nervure, the nervures of the secondaries, 

 except the discal, the inner margin next the base, and a band 

 crossing the cell, which is the extension of the third superior ner- 

 vule ; the markings of the primaries are heaviest towards the outer 

 border, those of the secondaries away from it ; the costal border 

 of the secondaries at base is slightly tinged with saffron ; the color 

 of the under surface of the wings is slightly dirty white, tinted with 

 very pale greenish-yellow, especially noticeable on secondaries and 

 upper half of primaries ; when any color is present on the prima- 

 ries of oleracea it is confined to the tip ; it differs further from 

 oleracea in having the black scales at base of both wings above 

 more profuse and widely spread, frequently bordering the nervures 

 quite broadly; indeed grayish scales are more or less scattered 

 over the whole of the upper surface, giving the insect a grim ap- 

 pearance, increased rather than diminished by the slightest possible 

 yellowish tint. 



By this description it would be exceedingly difficult to distin- 

 guish this species otherwise than by immediate comparison with 

 both sexes of oleracea; the differences are more easily to be seen 

 than described, though the extreme limits of variation of oleracea 

 do by no means permit us to include within its boundaries this 

 comparatively persistent form ; it is more heavily marked than the 

 extreme of oleracea. 



Eastern Labrador. 



SCITDDER. 



In order the better to compare together some of our species of 

 Pieris, I introduce here descriptions of some new species of this 

 genus from our western coast. 



