318 LEPIDOPTERA OF NORTH AMERICA. 



only slightly increased in number, though the scales which border 

 it make a large spot, and are generally deficient in the greenish 

 tinge ; the narrow border is interrupted by the darker scales which 

 form the swollen tips of the arrow-head spots. 



These extremes of variation I have found most generally in the 

 male; in the other sex, I have not seen any specimens which had 

 these wings so nearly immaculate as that first mentioned, the 

 nearest approach to it being in specimens which discover a few 

 scattered scales along the borders of the nervures, the cross-bar of 

 arrow-head spots, reduced to an indefinite indistinct zigzag band, 

 and the central spot of yellow, bordered with gray scales quite in- 

 distinct. 



It may also be said of this species, as of P. oleracea, that these 

 differences are observable equally in any locality in which the in- 

 sect 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 caUidice, the Siberian leucodice, the South 

 American autodice, the Arabian glavcono7ne, and the South Afri- 

 can hellica. We have in temperate North America no represent- 

 ative of the European P. chlorodice. 



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

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

 duval to be the same (see Spec. Gen. I, 518). Four specimens 

 were obtained by an expedition sent out in the summer of 1860, 

 by the Lyceum of Natural History in Williams College, to Labra- 

 dor and Greenland; they were collected by Mr. A. S. Packard, 

 Jr., on Caribou Island, Straits of Belle Isle, and have been sent 

 me for examination with numerous other insects — it may be called 



SCUDDER. 



8. P. frigida Scudder. Proc. Bost. Soc. N. H. VIII, Sept. 1861, 181. 



Two of the specimens obtained were males and two females; 

 the shape of the secondaries of the male of fric/ida is as in the 

 female of oleracea, those oi 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 o^ frigida are relatively more quad- 



