MENDELIAN FACTORS IN THE SILKWORM. 
101 
As the above Table shows, our theoretical expectation fairly agrees with 
the actual figures. 
The fourth generation is also interpretable in the same way. 
B. Second example of the “modified dihybrids”. 
The parental population among which the crossing was made evidently 
consisted of individuals of various compositions. These different zygotic forms 
are designated as Class 1, 2 and 3. 
Table II. 
p, 
'f; 
Class 
Japanese 
Siamese zebra 
Zygotes 
Apparent character 
No. 
common white 
white 
Ratio 
Actual figures 
Expectation 
1 
ZNZN 
ZnZn 
zNZn 
all zebra 
all zebra 
all zebra 
2 
zNzN 
Znzn 
1 zNZn 
1 zebra 
291 
315 
1 zNzn 
1 common 
339 
315 
1 zNZn 
1 znZn 
2 zebra 
352 
365.0 
3 
zNzn 
Znzn 
1 zNzn 
1 common 
196 
182.5 
1 znzn 
1 plain 
182 
182.5 
Fi fzXZnj individuals of the first class in the above Table will give, 
when mated inter se, the following F . offspring : 
Table III. 
F, 
F, 
Zebra 
Gametes 
Zygotes 
Apparant character 
Ratio j Actual figures 
Expectation 
1) In the present analysis we shall give, for the sake of simplicity only those factors 
necessary for the interpretation of the case. 
