AS 
If the systematist were wrong, if all these forms of Planema 
epea and Ælymnias phegea were distinct species, it would be 
much easier for the philosopher to explain their characters by his 
special theory. Let me reiterate at this point that I am not defend- 
ing or attacking any one theóry, but only endeavouring to demon- 
strate the great importance of correct systematics for all theoretical 
considerations. 
We come now to the second kind of genuine resemblance, which 
we have termed heterotrope. Amongst the most frequently quoted 
cases of similarity are certain Papilios, e. g. the African Papilio 
dardanus and the Oriental Papilio polytes, whose polymorphic 
females resemble several other Butterflies. These Insects have 
given rise to quite a bulky literature in the pro and contra of 
natural selection. As Dr. DIXEY has already shown some of 
them, it is not necessary to bring them again before you; nor 
shall I enter at any length upon the arguments advanced to 
explain the phenomenon of polymorphism. But in passing I should 
like to mention three points : 
It is occasionally stated that mimetic resemblance is as a rule 
confined to the female sex. That is a misconception which has 
arisen from the facts 1) that among the Lepidoptera more females 
are mimetic than males, and 2) that the male is very rarely 
mimetic if the female is non-mimetic. The cases in which the 
resemblance is confined to the female sex are less numerous than 
those in which both sexes are mimetic. 
Itis further maintained in this connection that for constitutional 
reasons (being another sex) the female occupies a lower phyletic 
stage than the male and hence has preserved a more ancestral 
coloration, which is said to explain many instances of resem- 
blance. The weak point in this rule is that there are so many 
exceptions. The female is very frequently either in advance of the 
male or has a coloration which the male never possessed in the 
phylogeny of the species, especially females which are « mime- 
tic ». The white females of Papilio wgeus ormenus GUER. (1829), 
for instance, represent a direction of development of their own 
and certainly not an ancestral stage of the species. The black 
female of Papilio glaucus L. (1758) shows at a glance that it is a 
derivation from that female which resembles the male, and there- 
fore is younger than the male as regards coloration. The females 
of Papilio dardanus BROWN (1776) exhibit specializations in 
