Toyarua, On certain characteristics of the Silk-worm etc. 



Dominant. Recessive. 



6. The presence of striped markings. The absence of striped markings. 



7. Dark worms. Orange-red worms. 



8. The presence of the special markings. The absence of the special markings. 



General Markings. 



9. Chinese black. Moricaud. 



10. Moricaud. Normals. 



11. Normals. Smudged. 



12. Smudged. Pale. 



13. Pale. Pale-smudged. 



Colour-characteristics of the Cocoon. 



Now we shall observe the colour of cocoons. Regarding the 

 relation between Japanese white and European yellow, as we have 

 already reported in my previous papers, the yellow is dominant to the 

 white. The Japanese white is also recessive to the Japanese yellow 7 

 (Onodahime). When we crossed European yellow, Papillons noirs 

 with Japanese divoltine white, the segregation is quite complete 

 and they gave the proportion of yellow and w T hite in each mating, 

 as demanded by the Mendelian theory and the yellow is dominant 

 to the Japanese white. On the contrary, European whites, such 

 as Italian white, and Sina blanc, are dominant to Japanese or 

 European yellows. 



As the results of many series of experiments we are justified 

 in saying that there are two kinds of white breeds in the silk- 

 worm, one being dominant and the other recessive towards the 

 same yellow. As far as our experiments went, the majority of 

 European whites are dominant, some of them being a mixture of 

 both dominant and recessive whites. Most Oriental whites, on the 

 contrary, are recessive to the yellow and some other coloured 

 cocooners. 



If the crossing were made between such a mixed white breed 

 with yellows, the results would be quite different from that obtained 

 by normal mono-hybrid. 



Let us now represent the dominant white by WW and the 

 recessive white by ww and the yellow by YY. In a mixed white, 

 we may infer that there exist three kinds of whites having different 

 zygotic compositions, WW, Ww and ww. Hence in the Fj derived 

 from the white X the yellow, we expect to have the following 

 gametic combinations : 



1. WW X YY = WY = all white ,. 



2. Ww X YY = WY -\- wY = a mixture of white and yellow 



in an equal proportion. 



3. ww X YY = wY = all Yellow F r 



