GAMETIC COUPLING AND REPULSION IN THE SILKWORM. 
127 
Striped yellow 
177 
Striped white 
15 
Normal yellow 
14 
Normal white 
49 
Plain yellow 
1 
Total 
256 
The theoretical numbers calculated on the above ratio are given below 
together with the actual figures obtained : 
Expectation 
Actual figures 
Striped yellow 
154.9 
148 
Striped white 
13.1 
12 
Normal yellow 
12.3 
14 
Normal white 
42.9 
50 
Plain yellow 
0.8 
0 
Total 
224.0 
224 
We see that the theoretical expectation on this supposition shows a less 
accordance with the observed figures than that given in the foregoing lines. 
Ü) The case can also be explained by assuming a ) a complete repulsion 
between S and N, and b) a partial repulsion between N and Y. On such 
an assumption we may expect the similar gametic series as that given above 
i. e. 1 sNY, 7 SnY, 7 sNy, 1 Sny. 
In fact, we have at present no positive reason to preclude a partial 
coupling between S and Y against a partial repulsion between NT and Y. 
The fact, that a complete repulsion does occur between N and Y in certain 
cases (Repulsion, Case 1), is not sufficient in itself to disprove the occurrence 
of a partial repulsion between them, in as much as I have found, as will be 
described later, that in one case a partial coupling takes place between S 
and Y factors, while in other case a perfect coupling occurs between them. 
Nevertheless it seems more probable that the case mentioned above is 
due to a partial attraction of S and Y- The following case positively 
