the varying dominance of certain white breeds of the silk-worm, etc. 263 



from the former 3W : ly mixture does not remain true in the next 

 generation, wliile those from the latttir 3 w : i Y will establish itself 

 as a constant form. 



yellows inbred. 



1. yellow X yellow = YY X YY = all yellow. 



2. „ X „ = YY X wY = wY + YY = all yellow. 



3. ,, ., = wY X wY = WW -(- 2 wY -\- YY = i white : 3 yellows. 



Some yellow matings yield all yellow offsping, while the others 

 mixed offspring consisting of iw : 3Y. This is the result we have 

 often met with when we crossed Siamese yellow with Siamese white. 



To sum up graphically: 



white X yellow. 



(0 

 w. 



(2) 



Y. 



\ 



/ 



(3 \V 



I Y) 



(I W 



F3^1_(3W:iY) ^] f (3W:.Y) ^IJ (i W: 3 Y) 



(I W 



3 Y) 



all all , ,,. ,,, 

 W. Y. (■^^•3^) 



Let us compare now our results calculated with those actually 

 obtained by Coutagne ('02) and Kellogg ('08). Firstly we shall quote 

 Coutagne's figures from his valuable paper entitled "Recherches ex- 

 perimentale sur I'heredit^ chez les vers a sole". We tabulate them 

 as below: 



