Mimetic Patterns to the Original Form. 67 
Pieris we get a great lightening of the general tone of 
colour, without however losing the essential features now 
referred to. In P. phaloe for instance, also a non- 
mimetic Pieris from the same neotropical region, we have 
as it were an attenuated and washed-out version of the 
scheme of marking seen on the hindwing of P. locusta. 
Here (Fig. 2) are visible the same basal red patches, 
though now confined to the precostal and internal spaces ; 
the same pale costal streak and central area, now in most 
specimens white rather than yellow; and on either side 
of the latter the same two dark shades, now reduced to 
a pair of brownish streaks. From either of these types 
to the well-known Heliconine form here represented by 
Heliconius numata (Fig. 11), seems a sufficiently long 
step; nor is it at first sight apparent that there is any- 
thing in common between the former and the latter 
schemes of coloration. Nevertheless, while it will be 
allowed on the one hand that the female of Mylothris 
pyrrha (Figs. 9, 10) presents a very good imitation of 
H. numata, it can be shown on the other hand that this 
last-named Pierine owes its mimetic features to a simple 
development of characters already possessed by the 
other Pierine forms just spoken of, to which it is closely 
allied. 
In order to make this apparent, it will be necessary to 
refer to some of the other neotropical species of the 
same genus Mylothris. This interesting lttle group, 
comprising besides M. pyrria the closely related M. 
malenka, M. lypera, and M. lorena, has been more than 
once spoken of by Mr. Wallace* as affording an instance 
of mimetic females associated with males of the ordinary 
white type of Pierine coloration. It is quite true that 
all the males throughout the group exhibit on their upper 
surfaces nothing but the ordimary white character; Mr. 
Wallace, however, does not mention the curious fact 
that the same males universally show on the under 
surface, though in varying degrees, an approach towards 
the Heliconine pattern that is so completely imitated 
by their mates. These partially developed features on 
the under surface of the males enable us to trace the 
history of the growth of the mimetic pattern. 
Let us take the underside of the male of Mylothris 
© “ Tropical Nature,” 1878, p. 204 ; “ Darwinism,” 1889, p. 271. 
