24 INHERITANCE IN SILKWORMS, I 



Mating Istrian, golden-yellow cocoon, with Chinese White, pure 

 white cocoon race, produced all golden-yellow cocoons ; also mating 

 Istrian with Japanese White, pure white cocoon race, produced all 

 golden-yellow cocoons; but mating Istrian with Bagdad pure white 

 cocoon race produced (in some instances) all white cocoons. In fact 

 although the cocoon character of most white cocoon races is recessive 

 in matings with the yellow, green or salmon colors of other races, the 

 white cocoon character of the Bagdad race is dominant in most crossed 

 race matings. 



The importance of this matter of a difference in inheritance be- 

 havior of the same characteristic in different strains and in different 

 individuals of the same strain leads me to offer in some detail an 

 account of the data obtained from several series of rearings. These 

 data will reveal also certain irregularities in the inheritance behavior 

 which make it difficult or impossible for me to accept Toyama's sweep- 

 ing conclusions as to the rigorous alternative and Mendelian or in 

 any way thoroughly consistent behavior of the silkworm cocoon colors. 

 In fact my whole work disposes me to be very chary of accepting too 

 quickly the fascinating generalizations concerning the simplicity or 

 rigorous regularity of inheritance behavior. There is no doubt in the 

 world that the Mendelian discoveries and conclusions are a great step 

 forward in our understanding of inheritance phenomena. That they 

 are as widely or as rigorously applicable as some Mendelian disciples 

 assume I doubt very much. 



Data of a series of crossings between Bagdad, pure race, bluish- 

 white larva, white cocoon, and Istrian, pure race, clayey-white larva, 

 golden-yellow cocoon. 



Fi (^ Istrian X 5 Bagdad; produced all golden-yellow cocoons. 

 F2 Hyb. yellow X hyb. yellow; produced 64 yellow, 24 white 



cocoons. 

 F2 Hyb. yellow X hyb. yellow; produced 61 yellow, 28 white 

 cocoons. 

 Fi (^ Bagdad X 5 Istrian ; produced all white cocoons. 



F2 Hyb. white X hyb. white; produced yy white, 17 yellow 



cocoons. 

 Fg Hyb. white X hyb. white; produced 62 white, 15 yellow 

 cocoons. 

 FjL ^ Bagdad X $ Istrian; produced 31 white, 21 yellow cocoons. 

 F2 Hyb. white X hyb. white; produced 57 white, 31 yellow 

 cocoons. 



