104 



belong, I think, specimens in the Museum of Comparative Zoology, 

 from Osage River, Missouri, which are very large, — males and 

 females alike measuring two and one-half inches in expanse of 

 wings, and having the under surface of secondaries pure yellow, 

 without any dusky scales. Here, also, belongs a pair of specimens, 

 taken in coitu, in Illinois, in Mr. Edwards's collection, — the male 

 of which has the wings yellow, but plainly tinged with orange on 

 the disc ; the only specimen of C. Philodice which I have seen with 

 any orange tint upon it. 



To this species, also, must be referred all the species indicated by 

 Fitch in the 13th vol. of the Transactions New York State Agricultural 

 Society, as Chrysotheme var. A, PMcomone, Nastes and Santes, — the 

 three former of which are not the species so named by European au- 

 thors, and the last of which is named only from a dwarfed specimen of 

 C. Philodice, equally small individuals of which I have seen in Mr. 

 Edwards's collection. It should also be added here that Dr. Fitch 

 leads us into an error when he states that they may all doubtless 

 be considered as but "varieties of two species, the Philodice and 

 Phicomone of Godart, — the latter having a row of yellow spots in 

 the black border of the upper wings in both sexes, whilst the former 

 has these spots in the females only ; " for we have no species here 

 having a row of yellow spots in the marginal border of the males, 

 and so at all referable to Phicomone. 



It would seem as if the genus Colias might properly be divided 

 into three sections : — 



1°. Those having a glandular space at the base of the secondaries 

 in the males. 



2°. Those wanting this space, and having the two sexes of the 

 same color. 



3°. Those wanting this space, with the sexes of different colors. 



Of the first section, none have been found in North America. 

 To the third seem to belong all and only the boreal species. 



There are two kinds of females of C. Philodice. One, by far the 

 most common, is of the same yellow color as the male, or very 

 nearly the same ; the other is whitish, about the tint of C. Hyale, 

 or even much paler. I have seen some considerable variation in 

 the depth of tint in both, but never any specimens through which 

 a gradation could be shown from one to the other, — they are 

 either of one tint or the other, — nor have I seen this albinism 

 ever exhibited in the males. This does not leave us in doubt that 

 C. Philodice should be placed in the second section, for the white 

 females are of great rarity. 



I have examined a large number of specimens from California 

 and Washington Territory, obtained by Mr. Agassiz, which 



