WARNING COLORATION AND MIMICRY The skunk as an example of warning coloration--Warning colours among insects--Butterflies--Caterpillars--Mimicry--How mimicry has been produced--Heliconidae--Perfection of the imitation--Other cases of mimicry among Lepidoptera--Mimicry among protected groups--Its explanation--Extension of the principle--Mimicry in other orders of insects--Mimicry among the vertebrata--Snakes--The rattlesnake and the cobra--Mimicry among birds--Objections to the theory of mimicry--Concluding remarks on warning colours and mimicry.