l8 INHERITANCE IN SILKWORMS, I 



In crossing yellow with green, first generation results were: in 

 Istrian Yellow X Japanese Green, offspring were all yellow ; in Persian 

 Yellow X Japanese Green, a majority of the young were yellow, a 

 minority green (numbers too small to be of significance as to propor- 

 tions) ; in Italian Yellow X Japanese Green, majority of the offspring 

 were yellow, minority green (numbers were too small to be of 

 significance as to proportions). 



In crossing white and green, first generation results are: in 

 Bagdad White X Japanese Green, all offspring are yellow. 



In crossing yellow and salmon, as in Persian lemon Yellow X 

 Italian Salmon, the offspring represented all shades from pale salmon 

 to golden yellow; in Istrian golden Yellow X Italian Salmon, the 

 offspring were salmon. 



In crossing white and salmon as in Bagdad White X Italian 

 Salmon, salmon is usually dominant (numerous cases of the domi- 

 nancy of white, however, see Strain and Individual Idiosyncrasies) 

 but the cocoons are not of single salmon tint characteristic of the 

 Italian Salmon race but are of all shades from very pale or whitish 

 salmon to very yellowish salmon or indeed definitely yellow even 

 golden. But in second generation lots produced by intermating 

 hybrids the white color usually appears again as a Mendelian recessive 

 distinct from the pale to yellow salmon shades constituting a Men- 

 delian dominant. In some white and salmon crosses as Italian White X 

 Italian Salmon, white was dominant. For example of the breaking of 

 salmon into all shades of pale salmon to golden-yellow: 



F i c? Bagdad White X ? Italian Salmon; produced all salmon 

 cocoons. 



F 2 Hyb. salmon X hyb. salmon; produced 28 pale to yellow 



salmon and 7 white cocoons. 



F 2 Hyb. salmon X hyb. salmon; produced 30 pale to yellow 

 salmon and 15 white cocoons. 



F! (J Italian Salmon X Bagdad White; produced all yellowish 

 salmon to strong yellow cocoons. 



F 2 Hyb. yellow salmon X hyb. yellow salmon; produced 23 



pale to yellow salmon and 19 white cocoons. 

 F 2 Hyb. yellow salmon X hyb. yellow salmon; produced 50 

 salmon to yellow and 16 white cocoons. 



The behavior of cocoon color crosses is evidently so erratic (at 

 least is apparently so erratic) that it may more appropriately be dis- 

 cussed in the section on "Strain and Individual Idiosyncrasies" rather 



