20 INHERITANCE IN SILKWORMS, I 



parents, as where all the young of a cross-mating between a tiger- 

 banded larva, salmon cocoon race, as Italian Salmon, and a white larva 

 white cocoon race as Chinese White, being tiger-banded larvae spinning 

 salmon-colored cocoons. But these cases of coincidence in both larval 

 and cocoon characters being those of either the father or the mother 

 are really only coincidences in the possession by the one parent of the 

 two dominant members of a double pair of allelomorphs. It is still 

 the dominance of the character and not of the parent that determines 

 the condition of the offspring as concerns the appearance or lying 

 latent of the character in question. 



It is unfortunate that none of the adult characters has yet been 

 found to be of the alternative Mendelian inheritance type, so that a 

 comparison of the transmission of characters in all three stages, larval, 

 pupal and imaginal, might be made. The adult variations in wing- 

 pattern and in the color and adhesiveness of the eggs are fluctuating 

 and not alternative in character. 



Prepotency of Sex and Vigor. 



It was desired to determine whether the dominance of a character 

 in heredity could be weakened or destroyed by weakening or lessening 

 the vigor of the parent representing the character, or whether in 

 general any prepotency in heredity was due to vigor or sex. 



Experiments were begun, therefore, in 1904 by rearing certain 

 individuals under conditions of short food and others of full food and 

 making matings between these starvelings and full-fed vigorous in- 

 dividuals. The individuals used for experiment were selected so as to 

 represent two races offering a Mendelian pair of allelomorphs both as 

 to larval and cocoon characteristics. Examples of these 1904 matings 

 and their results are as follows : 



A male starveling of race Italian Salmon, zebra larva, salmon 

 cocoon, was mated with a full-fed, vigorous female of race Chinese 

 White, unpatterned white larva, white cocoon. The young were all 

 zebra larvae. 



A male starveling of Italian Salmon race, zebra larva, salmon 

 cocoon, was mated with a full-fed, vigorous female of race Chinese 

 White, unpatterned white larva, white cocoon. The young were 70 

 zebra larvae and 75 unpatterned white larvae; all the cocoons were 

 salmon. 



A full-fed, vigorous male of Italian Salmon race, zebra larva, 

 salmon cocoon, was mated with a starveling female of Japanese White 



