240 
GENETIC STUDIES ON THE SILKWORM 
assume that the antagonistic characters are the more irregularly intermingled 
the later the mutations occur in blastomeres. From this point of view, the 
"right-left mosaic" should be produced by a single early or major mutation, 
while other mosaics should be produced by a major and some later or minor 
mutations ("mutation epidemic" !). The specimens given in Figs. 74, 75 and 
76 may be regarded as have resulted from some minor mutations preceded 
by no major one. 
The mosaic 6 interests us, because it assists to a fuller understanding of 
the size inheritance in the silkworm. Under ordinary circumstances, the 
proving of this inheritance meets with insurmountable difficulty, because it is 
practically impossible to place the individuals under exactly the same con- 
dition. The present case is, of course, quite free from this objection, and 
yet one side is markedly smaller than the other. 
VIII. SUMMARY. 
The more important results of this paper may be summed up as follows. 
1) The genetic factors for larval markings in the silkworm are six: 
S striping factor, P plain factor, 
M moricaud factor, Z zebra factor, 
Q .quail factor, L multiiunar factor. 
2) The zygotic constitutions of the more common markings are as follows: 
Striped 
SmPGzl 
Normal-zebra 
smPQZl 
Moricaud 
sMpazi 
Multilunar-plain 
sraPqzL 
Normal 
smPGzl 
Multi lunar-normal 
smPQzL 
Quail 
smpQzl 
Multilunar-normal-zebra 
smPßZL 
Plain 
smPqzl 
Striped-quail 
SmpCizl 
Pale-quail 
smpqzl 
Moricaud-quail 
sMpGzl 
Plain-zebra 
smPqZl 
Striped-quail-zebra 
SmpGZl 
Striped-zebm 
. SmPGZl 
Multi lunar-quail-moricaud 
sMpfizL 
etc. 
etc. 
Q factor is 
completely 
coupled with S and M in both sexes. 
