No. 533] INHERITANCE IN CO LI AS PIIILODICE 259 



in color and the common occurrence of the alhinic female, 

 a few specimens have been taken of an extremely rare 

 mutation, the melanic male, in which the yellow is re- 

 placed by smoky black, the margin being distinctly paler 

 than the ground color. In geographical distribution this 

 aberration does not seem to follow the general rule laid 

 down by Scudder that melanic forms occur in the southern 

 part of the range of a species, for two of the specimens 

 were from near Montreal, three seen and one captured 

 at Palmyra. X. Y.. and one now in the collection of Mr. 

 H. P. Kichardson, of Concord. Mass., was taken at Plain- 

 field, Mass. 



Partial melanism, or a melanistic tendency, often occurs 

 in the female, though complete melanism has been found 

 so far only in the male. This tendency reappears in suc- 

 cessive generations independently of the environment, in 

 certain strains that I have bred, though I think it pos- 

 sible that the action of the surroundings on certain indi- 

 viduals in a plastic condition may turn the germ cells in 

 this direction. I have not yet had an opportunity to test 

 this supposition, and my observations have been almost 

 entirely directed to the inheritance of the albinic variety 



Albinism in the genus Colias is due to the replacement 

 of yellow pigment with another which is white i Fig. 3), 

 all other pigments (black, red, etc.) remaining the same. 

 The white is sometimes tinged with yellow, but there is a 

 Bharp difference between the color of a typical yellow 

 female and that of the albinic form. 



Albinism is not entirely confined to the females, though 

 among the 900 descendants of white females that I have 

 raised there has been not one white male. White males 

 may be expected in regions where the white female is 

 specially abundant. At Hanover, N. H., the proportion 

 °f white females to yellow is, perhaps, roughly live per 

 cent. At Ithaca, N. Y., Professor Macgillivray informs 

 me, the proportion of white females is considerably 

 larger, being perhaps 10 or 15 per cent., and at Milton, 

 Mass., Mr. W. L. W. Field estimates them at 20-25 per 

 e(a nt. i n two localises where the white male has been 



