66 Dr. F. A. Dixey on the Relation of 



The instance chosen by Fritz MilUer 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 Lejitalis 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. euniara, which is itself 

 an almost exact copy of Actinote 'pellenea ; Actinote being 

 the neotropical representative of the well-known inedible 

 genus Acrsea. 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 III. 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 Pleris 

 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 (/), 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 (/i, i) 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. 



