GENETIC STUDIES ON THE SILKWORM 
Totals 492 468 963 
An absolute recessive female mated with a double hybrid, 
i. e. pqypqy ° x pöYpqy J . 
Quail yel. Quail wh. Pale-quail yel. Pale-quail \vh. Total 
A 424' 1 5 131 22 23 Iii 287 
Thus we know that Q-Y coupling always occurs in the same form in the 
hybrids PPQqYy, PpUqYy and ppftqYy. 
Summary of the data given above with respect to Q,-y coupling : 
QYqy x QYqy 
QY 
Qy 
qY 
qy 
Total 
Observed 
336i 
376 
294 
910 
4941 
Expected 
3396-9 
308.8 
308.8 
926.5 
494 1.( 
Ratio 
1 [ 
: 1 : 
1 : 
3 
aYqy 
2* x qyqy 
QY 
•Qy 
qY 
qy 
Total 
Observed 
984 
0 
0 
940 
1924 
Expected 
962 
0 
0 
962 
1924 
Ratio 
1 
1 
qyqy £ £ * QYqy 
m- 
QY 
Qy 
qY 
qy 
Total 
Observed 
719 
207 
186 
614 
1 726 
Expected 
647 
216 
216 
647 
1726 
Ratio 
3 
: I : 
1 : 
: 3 
The result from the cross PqyPqy ?? x PQYPqy approximates the 
numbers expected on the 3:1:1:3 basis, as shown below : 
Norm. yel. Norm. wh. PL yel. PI. wh. Total 
Observed 266 85 75 207 633 
Expected 237.4 79.1 79- 1 237.4 633.0 
2) Correlation of Moricaud Marking and Yellow Cocoon Character. 
A. M-Y Repulsion. 
The moricaud is epistatic to all other markings but the striped, to which 
