181 



ferences are observable equally in any locality in -which the insect 

 may be found, and the gradation is complete, though I have not as 

 yet seen any heavily marked males from the extreme western limit of 

 their range, but all I have examined have been nearly immaculate. 



P. protodice is the American representative of the European 

 daplidice, the Alpine callidlce, the Siberian leucodice, the South 

 American autodice, the Arabian glauconome^ and the South African 

 hellica. We have in temperate North America no representative of 

 the European P. chloridice. 



In eastern Labrador there is a white butterfly, very closely allied 

 to, but yet distinct from P. oleracea. It was considered by Boisduval 

 to be the same (see Spec. Gen. i. 518). Four specimens were ob- 

 tained by an expedition sent out in the summer of 1860, by the 

 Lyceum of Natural History in Williams College, to Labrador and 

 Greenland ; they were collected by Mr. A. S. Packard, Jr., on 

 Caribou Island, Straits of Belle Isle, and have been sent me for ex- 

 amination with numerous other insects ; — it may be called 



PlERIS FRIGIDA (n. Sp.) 



Two of the specimens obtained were males and two females ; 

 the shape of the secondaries of the male of frigida is as in the 

 female of oleracea^ those of frigida being proportionally narrower 

 across the hind margin, and broader across a line parallel to it, near 

 the base of wing, than in the same sex in oleracea ; or in other words, 

 the secondaries of frigida are relatively more quadrate, 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 ex- 

 tends 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 locaHty, 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 

 nervule ; the markings of the primaries are heaviest towards the 

 outer border, those of the secondaries away from it ; the costal bor- 

 der 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 primaries 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 ; in- 



