at birds? Would they not at once identify the harmless one
with their real enemy and thus fear them both alike? If the latter
were newcomers and vastly in the minority, then the ruse might work
for a while. But if there were ten harmless hawks around to one
dangerous one, the former would quickly suffer from the character of
the latter in the estimation of the birds. Birds are instinctively
afraid of all hawk kind.

Wallace thinks it may be an advantage to cuckoos, a rather feeble
class of birds, to resemble the hawks, but this seems to me
far-fetched. True it is, if the sheep could imitate the wolf, its
enemies might keep clear of it. Why, then, has not this resemblance
been brought about? Our cuckoo is a feeble and defenseless bird also,
but it bears no resemblance to the hawk. The same can be said of
scores of other birds.

Many of these close resemblances among different species of animals
are no doubt purely accidental, or the result of the same law of
variation acting under similar conditions. We have a hummingbird moth
that so closely in its form and flight and manner resembles a
hummingbird, that if this resemblance brought it any immunity from
danger it would be set down as a clear case of mimicry. There is such
a moth in England, too, where no hummingbird is found. Why should not
Nature repeat herself in this way? This moth feeds upon the nectar of
flowers like the hummingbird, and why should it not have the
hummingbird's form and manner?

Then there are accidental resemblances in nature, such as the
often-seen resemblance of knots of trees and of vegetables to the
human form, and of a certain fungus to a part of man's anatomy. We
have a fly that resembles a honey-bee. In my bee-hunting days I used
to call it the "mock honey-bee." It would come up the wind on the
scent of my bee box and hum about it precisely like a real bee. Of
course it was here before the honey-bee, and has been evolved quite
independently of it. It feeds upon the pollen and nectar of flowers
like the true bee, and is, therefore, of similar form and color. The
honey-bee has its enemies; the toads and tree-frogs feed upon it, and
the kingbird captures the slow drone.

When an edible butterfly mimics an inedible or noxious one, as is
frequently the case in the tropics, the mimicker is no doubt the
gainer.

It makes a big difference whether the mimicker is seeking to escape
from an enemy, or seeking to deceive its prey. I fail to see ho