330 Dr. Frederick A. Dixey on 
mimetic systems, is liable to be carried off in this or that 
direction as it comes under their influence. Sometimes, 
as in the forms that were discussed at the beginning of 
this paper, we find several species, closely related to one 
another by affinity, being drawn away in different direc- 
tions by the attractive power of the Miillerian groups 
that surround them; and the same assemblage of cases 
illustrates the fact that a mimetic change from the original 
form in the direction of one protected group may serve 
as a stepping-stone for a further departure towards 
another.* Sometimes again, as in Mylothris lypera, M. 
lorena, M. malenka, and M. pyrrha, we see that in the 
males a compromise is struck between the ordinary 
Pierine aspect (used for flight), and a mimetic dress hike 
that of the female (used for repose); while in Preris 
locusta we find the same compromise in the male, with 
the curious difference that here even the sexes of the same 
species have been wrested apart into separate mimetic 
relations. 
Finally, the comparison will perhaps not seem too far- 
fetched, if the several mimetic groups, each with its own 
type of coloration, are likened to the solar and stellar 
systems of astronomers. Sometimes, as in the solar 
system, there is one central body (7.e., species) dominat- 
ing the whole, and influencing its attendant planets (¢.e., 
mimics) to an extent in comparison with which the force 
they themselves can exercise is insignificant. At other 
times, as in the systems of double and multiple stars, 
there are bodies-(¢.e., species) more nearly equal in mass 
and importance, bound together by mutual attraction 
into a single combination, where each one effectively 
controls and is controlled by the rest. We may even 
push the comparison so far as to find an analogy between 
those irregular wanderers through cosmic space which 
from time to time get drawn within the limits of some 
* E.g., as was pointed out above, forms lke Pieris pandosia, 
P. leptalina, etc., show the result of attraction by the zxachia group 
upon Pieris of the ordinary kind. Similarly the yellow female 
of P. demophile exemplifies the ordinary form attracted in another 
direction, that of the agna combination, Again, the last-named 
development of Pieris has served as a basis for a further attraction, 
that by Heliconius charitonia, as seen in P. viardi 9 ; and this latter 
form has given scope for the influence of the atthis group as shown 
by P. locusta 9. 
