No. 533] INHERITANCE IN COLIAS PHILODICE 263 



that the mother would produce no white offspring. (2) 

 Yellow females under certain conditions do produce both 

 yellow and white offspring. Thus the mothers of fami- 

 lies "e," "f," "i," and "k," 1910, were yellow, produc- 

 ing, respectively: ]:? white and U yellow daughters; 7 

 white and 5 yellow; 30 white and 14 yellow; 19 white and 

 19 yellow. The conditions under which these four yel- 

 low females produced white offspring were alike. The 

 female and the brother with which she mated were in each 

 case the immediate offspring of a white female, the male 

 mate in each case being presumably heterozygous for 

 color, y(w), the yellow female homozygous for that 

 color, yy. 



1. Inheritance of the White Female 



Summary of Results 



My observations, begun in the fall of 1908 and extend- 

 ing through the two following seasons, some of the same 

 stock now being in hibernation, may be summarized as 

 follows : 



1. The white female, of which I have tested 13 indi- 

 viduals, is in all cases heterozygous for color, producing 

 when crossed with a pure yellow male (wild, or her own 

 brother), either e<|ual numbers of white and of yellow 

 female offspring, in accordance with Mendelian expecta- 

 tion (stock from Cambridge, Mass., families a, b, c, d, 

 1910), or twice as many yellow females as white (stock 

 from Hanover, N. H., families a and c, 1909). The male 

 offspring of a heterozygous white female are all yellow, 

 though presumably one half are heterozygous, y(\v), and 

 one half homozygous dominants, yy. 



2. It is evident from these observations that white is 

 dominant in the female, yellow in the male, these being 

 the colors of the respective heterozygotes. This case is 

 comparable to the results obtained by Wood in crossing 

 horned Dorset with hornless Suffolk sheep, the male 

 heterozygote of F, having bonis, the ewes being hornless. 

 The horned condition is therefore dominant in the male, 

 while in the female hornlessness is dominant. 



