234 Toyama and Mori. 
9 Japanese white > 3 European white. 
(Fı.) 
Table I. 
No. of matings Number of cocoons produced colour of cocoons 
263 | white 
142 | 5 
4*) | 273 n 
7 | 203 ” 
8 326 a 
9 | 312 , 
10 271 ) 
II 316 
12 238 > 
Total: 2,344 all white. 
9 matings gave 2,344 white cocoons, no yellow-coloured ones. 
Minute examination, however, showed that, as in the European 
parent breed, there were great variations of shading, ranging from 
light greenish yellow to white. We divided them into nine classes 
according to the depth of colour, the first class being the deepest 
and the ninth lightest or no shade. Moths derived from each class 
were paired inter se for the experiments made with the F, generation. 
Fy. 
Owing to the absence of Toyama from our laboratory on a tour 
of Europe, the F, generation was reared by Mori in the spring of 
1912. It gave the following offspring: 
Colour of cocoons 
Parentage No. of matings ——— - Total 
white yellow 
No. 4 (znd class) I 286 68 | 354 
2 217 62 | 279 
3 294 77 371 
4 224 34 258 
5 255 56 311 
6 209 40 249 
i 223 55 278 
8 264 70 334 
9 377 93 479 
Total: | 2,349 (80.9%) 555 (19%)| 2,901 
Expectation: 81.2605 18.75% — 
13 2 Be 
*) The mating marked with an asterisk is the parent of the next generation. 
