1^2 GENETIC STUDIES ON THE SILKWORM 
are produced. Striped-zebra, multilunar-zebra, moricaud-zebra, multilunar- 
striped, multilunar-moricaud, and any combination of zebra and multilunar 
with other types may be obtained by due crossing. The chocolate series 
differs from the ordinary or melanic series in lacking the black factor B, but 
runs, in other points, exactly parallel with the latter. When B is absent, the 
just hatched larva ("ant") is, whatever its ultimate marking may be, reddish 
brown in distinct contrast to the ordinary black. Through the whole larval 
life the chocolate character usually comes out distinctly in all marking of 
b-series with the only exception of plain which is entirely devoid of marking. 
It has been shown in my previous works (191 3 a,b), that striping is epi- 
static to moricaud, and moricaud to normal, and normal to plain. Let us 
now turn to examine the behaviour of pale-quail and quail towards other 
marking types. 
As is described in future pages, there exists a great variation in regard 
the pigment intensity of normal as well as quail, ranging from the forms 
with lightest eye-spots to those with darkest. It is not a rare occurrence that 
lightest normal or quails (with faintest "eye-brows") appear in the offspring 
of crossing plain or pale-quail (the types with no "eyebrows") with one of 
the distinctly "eyebrowed" types (normal, quail, striped and moricaud). This 
phenomenon probably depends upon the existence of multiple factors concern- 
ing the marking in question; the point will be dealt with later in more detail 
(Chapter VI). For the moment, there is no great inconvenience for theoretic- 
al analysis, if we count the lightest normal with the plain, and the lightest 
quails with the pale-quails. Such heterogeneous classes are marked with an 
asterisk * in this and the following chapters. 
When pale-quail is paired to plain, F ± generation consists of only plain 
which split, in the next generation, into 3 plain and 1 pale-quail. 
Plain Pale-quail Total 
A 39 i'i 5 308 82 390 
Ratio 3 : 1 
F L hybrids back-crossed to the recessives gave plain and pale-quail in about 
