228 
GENETIC STUDIES ON THE SILKWOKK. 
Fj 3-moulters mated inter sc. 
3-moult. 
4-mouit. 
Ratio 
A 7 8 5 'i 5 
148 
50 
3 
1 
A 7 86'i 5 
196 
68 
2.9 
1 
A 78/15 
173 
60 
2.9 
1 
A 7 SS'i5 
231 
48 
4.8 
1 
Totals 
74S 
226 
3-3 
1 
Expect. 
730.5 
243-5 
1 
F 2 3-moulters 
x 4-moulters. 
A 7 8 3 'i 5 
169 
157 
1.1 
1 
A 784' 1 5 
161 
207 
1 
A 7 8 9 'i 5 
O -> "> 
212 
1.1 
1 
Totals 
552 
576 
1 
: 1 
Expect. 
564 
564 
1 
1 
4-moulters X 
F x 3-mou 
Iters. 
A 7 82'i 5 
0 j -> 
194 
1.1 
: 1 
A 790' 1 5 
156 
176 
1 
: 1.1 
Totals 
368 
370 
1 
: 1 
Expect. 
369 
369 
1 
: 1 
I have many other cases which gave monohybrid ratio in inheritance of 
moulting character, but they need not, I believe, be added here. 
The moulting character is, on the other hand, subject to variation under 
environmental agencies. In some cases, 3-moulters or 5-moulters are found 
in families which are normally 4-moulting. Though usually small in number, 
the variants may sometimes attain a high percentage. In 191 1, in Nagano 
Province, for instance, 5-moulters appeared unexpectedly and were so numer- 
ous as to draw general attention ; the event is to be ascribed to certain 
physiological disorders caused by the volcanic ashes which repeatedly covered 
the mulberry-field during the year, as is demonstrated later by Yokota(i9I2) 
and Kawase and Kakasawa (191 5) in their experiments in which the 5 -moult- 
