KUR rilKR DA TA ON rill'. Ki;i jUI'l.ICATKJN IN SILKWORMS. 
7 
As above pccliL;rce shows the Iictorozy^ous striped )'l'11o\vs (No. 
297'! in the sprin;^ 19'3' liJ^^'c received tlic stri[)C(]iiL'ss from the mother, 
and the }-ello\vness from the father. Occurrence of j^anx'tic rei)ulsion 
between these dominant cliaractcrs may naturally be aii^icipated ^ as the 
result of such crossing, and practicall)' the figures obtained in the succeed- 
ing season represent the reduplicated series of the male parent as such, the 
Kasin-i white being absolute recessive to the striped \'ellow. 
Striped Striped Moricaud Moricaud Total 
yellow white yellow white 
Observed 82 173 164 69 488 
Expected on 
i : 2 : 2 : I basis ' ' ' j t 
Thus it is evident that a partial repulsion of lowest intensity takes 
jjlace in the i/ialc gametes of SsYy, ^\■hen the factors S and Y have been 
introduced by the different jiarents. We cannot tell with confidence at 
present what haj)pens in the fciiinic heterozygote, though there are some 
reasons in imagining occurrence of a complete repulsion in it. 
b) The Coupling between N and Y. 
As I have described in the separate paper (1914, I. c.) the repulsion 
between M" and Y that occiu's in the heterozygote ex NNyy x nnYY is 
partial in the male, but it is complete in the female. If If and Y were 
brought into the 'hybrid by the same parent, on the other hand, what 
there will be happened? The following result, though insufficient, jjoints 
to occurrence of at least some couplings, possibly 2 : i : i : 2 in q" — 
and complete in !^ , in such a cross. The pedigree and the actual numbers 
are diagramatically given below. 
1. The entire result in this generation is easily accounted for as follows. As the gametic 
series would have been i SY : i sy in the mother, and 3 MY : i My : i mY : 3 DHy i» t'le 
father (If-factor being understood), the offspring should l)c in the ratio 4 str. yel. : 4 str. wh. 
: 3 mor. 3'el. : I mor. wh. : I nor. yel. : 3 nor. wh. This has been precisely realised, the 
expectation being 63 : 63 : 47 : 16 : 16 : 47. 
2. Couplings arise, as stated elsewhere, in ex str. yel. X iion-slr. wh. 
