Phylogeny of the Pierinee. 297 
is advantageous for any two or more protected species 
to join their forces, in order to share the toll levied upon 
them by inexperienced enemies. In such cases it no doubt 
often happens that one species serves as the standard to 
which the others conform, whether by way of convergence 
or of arrested divergence ; but there seems no reason 
why, especially if there is no conspicuous inequality of 
numbers, there should not be akind of ‘ give and take ” 
arrangement between mimicker and mimicked, the latter 
advancing some way to meet the former for their mutual 
benefit. In other words, when two species, A and B, 
form an association of this kind, it need not be supposed 
that the form of A remains fixed, while B assimilates 
itself to it, or vice versa ; but the association may really 
be formed by both A and B converging towards a point 
between them, or, in short, mimicking each other. 
The acceleration of the process which in many cases 
would result, must of itself be an advantage. Now if 
the grouping of kindred inedible forms in associations of 
this kind is beneficial, it would seem that the benefit 
might extend to members of families far removed from 
one another, like the three now under discussion, as well 
as of the same family or genus;* the only requisites 
being (1) that all should be more or less inedible, and (2) 
that all should have patterns capable of assimilation to 
one another. Nor does there seem to be any reason why a 
mutual convergence of the kind indicated should not 
take place under these conditions also. With respect to 
(1), it has, I think, nearly always been assumed that the 
Pierine which resemble the members of other families 
are edible; and this is no doubt the case with the 
numerous members of the genus Dismorphia + (Leptalis 
of Dalman), which were among the first to attract notice 
to the subject of Mimicry in general. But no direct 
proof seems to exist that the species of Huterpe and 
Pereute now under discussion are edible; and indeed 
Mr. Wallace considers (Trans. Ent. Soc. Lond., 3rd 
series, iv., pp. 309, 310; Darwinism, 2nd ed., 1889, 
* Such an association is already well known to occur between 
Heliconide and Danaide. 
+ This, however, has been questioned by Mr. Beddard, who cites 
some observations of Scudder as tending to show the contrary. 
See * Animal Coloration,” 1892, p. 215. 
TRANS. ENT. SOC. LOND. 1694.—PaRT I. (JUNE.) U 
