|
to the tricks of the stage? Mr. Bates has,
doubt, hit on the true explanation. The mocked forms, which always abound in numbers, must habitually
→to a large extent, destruction,
otherwise they could not exist in such swarms; and
→Mr. Bates never saw them preyed on by
birds and
→certain large insects which attack other butterflies;
→he suspects
that this immunity is owing to a peculiar and offensive odour
they emit. The mocking forms, on the other hand,
inhabit the same district, are comparatively rare, and belong to rare groups; hence they must suffer habitually from some danger, for otherwise, from the number of eggs laid by all butterflies, they
→if not persecuted, in
three or four generations swarm over the whole country. Now if a member of one of these persecuted and rare groups were to assume a dress so like that of a well-protected species that it continually deceived the practised eyes of an entomologist, it would often deceive
birds and insects, and thus
→escape entire annihilation.
may almost be said
→that Mr. Bates has
witnessed the process by which the mimickers have come so closely to resemble the mimicked; for he
that some of the forms of
→whether these be ranked as species or varieties, which
mimic so many other butterflies,
→vary much. In one district several varieties
and of these one alone
to a certain extent, the common Ithomia of the same district. In another district there
two or three varieties, one of which
much commoner than the others, and this closely
→mocks and
Ithomia. From
of this nature, Mr. Bates concludes that
→in every case the Leptalis originally
and
a variety
→arose which happened
to resemble in some degree any common butterfly inhabiting the same district, this variety, from its resemblance to a
little-persecuted kind,
a better chance
|
