GAMETIC COUPLING AND REPULSION IN THE SILKWORM. 1 23 
Lot No. Striped white Normal yellow Total 
H. 17. ’ll 63 65 128 
Here we have encountered a curious phenomenon. Two pairs of the 
characters by which the parents differed from each other appeared in an 
exactly-reversed combination in their offspring, that is to say, the striped 
larvae were all white-blooded instead of being yellow-blooded, and the normal- 
patterned were all provided with yellow blood instead of being white-blooded. 
As the parental formulae are known to be ssNNyy (Aojilcu) and SsnnYy 
(S. 5. ’ 1 1 striped yellow) respectively, we should expect, if the inheritance 
was normal, the offspring to be as follows : 
1 SnYsNy 
1 SnysNy 
1 snYsNy 
1 snysNy 
But as already stated such 
was not the case. 
Therefore we are forced 
to suppose that there occurs a 
perfect repulsion between the striped marking 
and the yellow colour. The case may be diagramatically expressed thus : 
1911 
Normal white > 
< Striped yellow 
ssNNyy 
SsnnYy 
Gametes 
sNy 
Sny, snY 
1912 
1 
Striped white 
1 
Normal yellow 
SnysNy 
snYsNy 
Ratio 
1 : 
1 
Observed 
63 
65 
Expected 
64 
64 
.Striped yellow 
• Striped white 
Normal yellow 
• Normal white 
I have had only one mating of this cross. But there seems to be no 
way of explanation other than that there takes place an absolute repulsion 
between stripedness and yellowness. Moreover, it is higldy probable that the 
