me that Belt's deeply interesting suggestion requires
much solid evidence and repeated confirmation before it can be accepted
as a valid interpretation of the facts. In the present state of our
knowledge, at any rate of insects and especially of Lepidoptera, it is
probable that the female is more apt to vary than the male and that an
important element in the interpretation of prevalent female mimicry is
provided by this fact.

In order adequately to discuss the question of mimicry and sex it would
be necessary to analyse the whole of the facts, so far as they are known
in butterflies. On the present occasion it is only possible to state the
inferences which have been drawn from general impressions,--inferences
which it is believed will be sustained by future inquiry.

(1) Mimicry may occasionally arise in one sex because the differences
which distinguish it from the other sex happen to be such as to afford a
starting-point for the resemblance. Here the male is at no disadvantage
as compared with the female, and the rarity of mimicry in the male
alone (e.g. Cethosia) is evidence that the great predominance of female
mimicry is not to be thus explained.

(2) The tendency of the female to dimorphism and polymorphism has been
of great importance in determining this predominance. Thus if the female
appear in two different forms and the male in only one it will be twice
as probable that she will happen to possess a sufficient foundation for
the evolution of mimicry.

(3) The appearance of melanic or partially melanic forms in the female
has been of very great service, providing as it does a change of
ground-colour. Thus the mimicry of the black generally red-marked
American "Aristolochia swallowtails" (Pharmacophagus) by the females of
Papilio swallowtails was probably begun in this way.

(4) It is probably incorrect to assume with Haase that mimicry always
arose in the female and was later acquired by the male. Both sexes of
the third section of swallowtails (Cosmodesmus) mimic Pharmacophagus in
America, far more perfectly than do the females of Papilio. But this is
not due to Cosmodesmus presenting us with a later stage of history begun
in Papilio; for in Africa Cosmodesmus is still mimetic (of Danainae) in
both sexes although the resemblances attained are imperfect, while
many African species of Papilio have non-mimetic males with beautifully
mimetic females. The explanation is probably to be sought in the fact
that t