Cras) 
Boisd. Besides this, f. semiflava, Auriv., at once suggests 
membership of a numerous assemblage characterised by brown 
upper and pale under-wings, to which group also belong many 
females of Mylothris spica, Mésch., Phrissura sylvia, Fabr., 
Belenois theuszi, Dewitz, and B. theora, Doubl. 
“The question naturally arises, what is the meaning of 
these resemblances? I am not credulous enough to believe 
that they represent a mere series of coincidences; it appears 
to me that they must have some bionomic significance, and that 
in the present as in similar instances the interpretation least 
attended with difficulty is that which attributes to them a 
mimetic value. It is generally admitted that M/ylothris, forms 
of which so often take a central position in these supposed mi- 
metic groups, isa well-protected genus. There is therefore good 
reason for its imitation by Z. argia, whether this imitation be of 
the Batesian or of the Miillerian kind. Itistrue that L. argia 
is seldom a very perfect mimic ; its various forms seem to hover 
on the outskirts of mimetic groups without entirely casting in 
their lot with them. But cases similar to this are known 
elsewhere ; and much the same, mutatis mutandis, might be 
said of many instances (which few would be found to dispute) 
of protective resemblance to inanimate objects. We find, 
indeed, as under the theory of adaptation by selection we 
should expect to find, every sort of gradation between protec- 
tion which is only slight, and protection which is all but 
complete ; and this, whatever be the special kind of protection 
in question. If a species be maintaining its ground, deficiency 
in one particular will be made up for by excellence in another. 
XXxi| 
‘**Some of the forms of L. argia, 2 , are restricted to definite 
regions, and it is natural to ask whether these mimics and 
their models are always to be found in the same locality. To 
a great extent this can be shown to be the case, but a wider 
knowledge than we at present possess of the distribution of 
both sets of forms would be necessary for a complete answer 
to the question. Meanwhile, the facts now at our command 
do not suggest an answer unfavourable to the theory. 
‘“‘T have heard it remarked that whereas the form swlphurea 
of L. argia, °, has a well-marked dark margin, the Mylothris 
