e a few imperfect, and one or two
very perfect cases of true mimicry to be found among them. The less
perfect examples are those presented by several species of cuckoos, an
exceedingly weak and defenceless group of birds. Our own cuckoo is, in
colour and markings, very like a sparrow-hawk. In the East, several of
the small black cuckoos closely resemble the aggressive drongo-shrikes
of the same country, and the small metallic cuckoos are like glossy
starlings; while a large ground-cuckoo of Borneo (Carpococcyx radiatus)
resembles one of the fine pheasants (Euplocamus) of the same country,
both in form and in its rich metallic colours.

More perfect cases of mimicry occur between some of the dull-coloured
orioles in the Malay Archipelago and a genus of large honey-suckers--the
Tropidorhynchi or "Friar-birds." These latter are powerful and noisy
birds which go in small flocks. They have long, curved, and sharp beaks,
and powerful grasping claws; and they are quite able to defend
themselves, often driving away crows and hawks which venture to approach
them too nearly. The orioles, on the other hand, are weak and timid
birds, and trust chiefly to concealment and to their retiring habits to
escape persecution. In each of the great islands of the Austro-Malayan
region there is a distinct species of Tropidorhynchus, and there is
always along with it an oriole that exactly mimics it. All the
Tropidorhynchi have a patch of bare black skin round the eyes, and a
ruff of curious pale recurved feathers on the nape, whence their name of
Friar-birds, the ruff being supposed to resemble the cowl of a friar.
These peculiarities are imitated in the orioles by patches of feathers
of corresponding colours; while the different tints of the two species
in each island are exactly the same. Thus in Bouru both are earthy
brown; in Ceram they are both washed with yellow ochre; in Timor the
under surface is pale and the throat nearly white, and Mr. H.O. Forbes
has recently discovered another pair in the island of Timor Laut. The
close resemblance of these several pairs of birds, of widely different
families, is quite comparable with that of many of the insects already
described. It is so close that the preserved specimens have even
deceived naturalists; for, in the great French work, _Voyage de
l'Astrolabe_, the oriole of Bouru is actually described and figured as a
honey-sucker; and Mr. Forbes tells us that, when his birds were
submitted to Dr.