GAMETIC COUPLING AND REPULSION IN THE SILKWORM. 
129 
calculated. 
Since there exists no “presence’ 5 factor other than those given above, i. e. 
stripedness and yellowness, there is least possibility of occurrence of other 
reduplicated systems in this case. 
II. Partial coupling between the moricaud marking (M) and the yellow 
colour (Y). 
In 1910 some of the Chinese moricaud yellow larvae were selected by 
their outer characteristics, and five matings were made among themselves. 
Of these matings, progeny of four were reared in 1911, each of which 
consisted of two different forms, moricaud yellow and plain yellow. The 
actual numbers of the larvae produced by these four matings taken together 
are 680 moricaud yellow and 232 plain yellow, which almost exactly 
represent the 3 : 1 ratio. 
A single mating (M. 7. ’10) shows, however, a little complication, 
giving the following offspring: 
Lot No. 
Moricaud yellow 
Moricaud white 
Plain yellow 
Plain white 
M. 7. TO 
104 
12 
5 
38 
Total 
159 
Apparently the result is accounted for by the assumption of a partial 
coupling between moricaud and yellow. The expectation on the 7 : 1 : 1 : 7 
series is as follows : 
Actual figures 
Expectation 
Moricaud yellow 
104 
109.9 
Moricaud white 
12 
9.3 
Plain yellow 
5 
9.3 
Plain white 
38 
30.5 
Total 
159 
159.0 
