3(1 Tanaka. 



That the study of results of cross between AaBb and aabb is 

 necessary in so-called complete repulsion, will be seen from the following 

 eonsidei-ation. In gametic repulsion of higher intensity an immense number 

 of Fi individuals is required for determination of the system, so that 

 the rearing of them is often rendered impossible. In the 1 : 63 system, 

 for instance, we may expect a single aabb form out of 16384, and only 

 one out of 65536 in the 1 : 127 repulsion. This difficulty can, however, 

 be overcome by making cross between AaBb and aabb forms. In the 

 offspring of such mating we may expect one aabb out of 128 in the 

 1 : 63 distribution, and one out of 256 in the 1 : 127 scheme, and so on. 

 There are many cases in which the intensity of the reduplication is 

 different in coupling and repulsion'). In such occasion the repulsion 

 is often apparently complete, but these are such cases for which the test 

 of gametic series by crossing with aabb is especially desirable. 



No racial peculiarities in herediüuy behaviour of the marking and 

 colour characters were found to exist in the present experiments. 



Dissimilarity of the reduplication system in male and female hybrids 

 may exist also in other cases of coupling or repulsion in the silkworm 

 than those mentioned above. Evidence for this is, among others, to 

 certain extent sufficient in the striped -yellow coupling, l)ut as more 

 complex relations appear to be present in connection with the stripedness, 

 I will prefer to describe the case in a separate paper. 



Refer the summarised list in Taxaka, 191.S b (1. c. pp. 1.37 — 142). 



