This excellent observer has shown that in some districts of South America, where, for instance, an Ithomia abounds in gaudy swarms, another butterfly, namely, a Leptalis, is often found mingled in the same flock; and the latter so closely resembles the Ithomia in every shade and stripe of colour, and even in the shape of its wings, that Mr.

Bates, with his eyes sharpened by collecting during eleven years, was, though always on his guard, continually deceived.

When the mockers and the mocked are caught and compared, they are found to be very different in essential structure, and to belong not only to distinct genera, but often to distinct families.

Had this mimicry occurred in only one or two instances, it might have been passed over as a strange coincidence.