cerned
here. Of these six forms three were purples and three were reds. The three
purple forms were (1) the wild bicolor purple with blue wings known in
cultivation as the Purple Invincible (Pl. IV., 4); (2) a deep purple with
purple wings (Pl. IV., 5); and (3) a very dilute purple known as the
Picotee (Pl. IV., 6). Corresponding to these three purple forms were three
reds: (1) a bicolor red known as Painted Lady (Pl. IV., 7); (2) a deep red
with red wings known as Miss Hunt (Pl. IV., 8); and (3) a very pale red
which we have termed Tinged White[5] (Pl. IV., 9). In the F_2 generation
the total number of purples bore to the total number of reds the ratio
3 : 1, and this ratio was maintained for each of the corresponding classes.
Purple, therefore, is dominant to red, and each of the three classes of red
differs from its corresponding purple in not possessing the blue factor (B)
which turns it into purple.

[Illustration: PLATE IV.

1, 2, Emily Henderson; 3, F_1 reversionary Purple; 4-10, Various F_2 forms:
4, Purple; 5, Deep Purple; 6, Picotee; 7, Painted Lady; 8, Miss Hunt; 9,
Tinged White; 10, White.]

{81} Again, the proportion in which the three classes of purples appeared
was 9 bicolors, 3 deep purples, 4 picotees. We are, therefore, concerned
here with the operation of two factors: (1) a light wing factor, which
renders the bicolor dominant to the dark winged form; and (2) a factor for
intense colour, which occurs in the bicolor and in the deep purple, but is
lacking in the dilute picotee. And here it should be mentioned that these
conclusions rest upon an exhaustive set of experiments involving the
breeding of many thousands of plants. In this cross, therefore, we are
concerned with the presence or absence of five factors, which we may denote
as follows:--

A colour base, R.
A colour developer, C.
A purple factor, B.
A light wing factor, L.
A factor for intense colour, I.

On this notation our six coloured forms are:--

(1) Purple bicolor CRBLI.[6]
(2) Deep purple CRBlI.
(3) Picotee CRBLi or CRBli.
(4) Red bicolor ( = Painted Lady) CRbLI.
(5) Deep red ( = Miss Hunt) CRblI.
(6) Tinged white CRbLi or CRbli.

It will be noticed in this series that the various coloured {82} forms can
be expressed by the omission of one or more factors from the purple bicolor
of