No. 533] INHERITANCE IN COLIAS PHILODICE 



271 



sumed or demonstrated to be the case. The eggs of the 

 white female are, accordingly, to be represented as fol- 

 lows : yx, yo, wx, wo ; those of the yellow female : yx and 

 yo. It is not necessary to assume in gametogenesis of 

 the heterozygous white female of Colias any repulsion 

 between one determiner and another resulting in a coup- 

 ling such as is believed to occur in Abraxas. The deter- 

 miner for yellow and that for white have equal chances 

 of passing into a gamete with the male determiner or 

 into one without it. 



There are, of course, nine imaginable sets of combina- 

 tions that would take place in the fertilization of the 

 eggs of a species with three sorts of females: yyox, 

 w(y)ox and wwox by the sperms of the males: yyxx. 

 y(w)xx and wwxx. We will consider first the combina- 

 tions that up to the present time actually have been made 

 in my cultures. 



1. The Pure Yellow Female x the Pure Yellow Male 



yyoxXyyxx 



yyxx, yyox = 50 per cent, pure yellow 50 per cent, pure yellow 

 (Brood 2y, 1909.) 



2. The Pure Yellow Female x Heterozygous Yellow Male 



25 per cent, pure yellow fa 25 per cent, pure yellow $$, 25 per cent, 

 heterozygous yellow 25 per cent, heterozygous^ white ??. all the 



bers. (Broods e, f, k, i.) 

 3. White Heterozygous Female x Pure Yellow Male 

 w(y)ox X yyxx 



Wx ' wo > yx, yo = gametes of the female 

 yx. yx= game tea of the male 

 ~?<yO*x, w(y)ox, yyxx, yyox 



c?o* 50 per cent, pure yellow, 50 per cent, heterozygous yellow, 



numbers. (Broods a, c, 1909; a-d, 1910.) 



