66 Dr, F. A. Dixey on the Relation of 
The instance chosen by Fritz Miiller was unfortunate. 
A wider view of Pierine affinities than he had the oppor- 
tunity of taking would no doubt have led him to the 
conclusion that, after all, the original Leptalis probably 
was a white or white and black butterfly, and not a black 
and yellow or black and orange insect like Leptalis 
(Dismorphia) melia. Moreover, the position that D. melia 
is not a mimic can hardly be sustained. It bears a very 
considerable resemblance to D. ewmara, which is itself 
an almost exact copy of Actinote pellenea ; Actinote being 
the neotropical representative of the well-known inedible 
genus Acrea. There is little room to doubt that D. melia, 
so far from preserving the primitive Leptalis type, has 
diverged to some distance therefrom under the influence 
of mimicry. 
But although Fritz Miiller’s principal instance does 
not appear to me to be strong enough to bear the weight 
of argument that he rests upon it, there cannot be much 
question that his contention in the main is _ perfectly 
sound ; and that, as a general principle, the process of 
mimetic assimilation depends rather on the development 
of old, than on the starting of new features, either of 
pattern or of colour. 
In order to illustrate this principle, I have prepared the 
series of figures shown in Plates IIT. and IV., Figs. 1-12. 
These represent an array of facts that I venture to think 
are in many respects of great interest. 
Fig. 1 shows the underside of the male of one of the 
ordinary neotropical non-mimetic Pierines*, a true Pieris 
as that genus is restricted by Dr. Butler—P. locusta of 
Felder. The chief points to be observed are in the 
hindwing. ‘They are (1), the spots or patches of bright 
red which are found at the base of the precostal, median 
and internal spaces respectively (Fig. 1, a, c,d); (2) a 
well-defined yellow streak (e) occupying the costal space ; 
(3) a pale central area (f'), in many specimens yellowish, 
occupying the region of the cell and the adjacent portion 
of the wing, especially towards the internal border ; 
(4) a dark shade (h, 7) on the anal and costal sides 
respectively of the pale central area. The present 
species happens to be a rather heavily coloured member 
of its group, but in other species of the same genus 
* See below, p. 72, note. 
