74 NATURAL SELECTION in 



usually olive-green or brown ; and in several cases these most 

 curiously resemble the Tropidorhynchus of the same island. 

 For example, in the island of Bouru is found the Tropido- 

 rhynchus bouruensis, of a dull earthy colour, and the Mimeta 

 bouruensis, which resembles it in the following particulars : 

 The upper and under surfaces of the two birds are exactly of 

 the same tints of dark and light brown ; the Tropidorhynchus 

 has a large, bare black patch round the eyes ; this is copied 

 in the Mimeta by a patch of black feathers. The top of 

 the head of the Tropidorhynchus has a scaly appearance, from 

 the narrow scale-formed feathers, which are imitated by the 

 broader feathers of the Mimeta having a dusky line down 

 each. The Tropidorhynchus has a pale ruff formed of curious 

 recurved feathers on the nape (which has given the whole genus 

 the name of Friar birds) ; this is represented in the Mimeta 

 by a pale band in the same position. Lastly, the bill of the 

 Tropidorhynchus is raised into a protuberant keel at the base, 

 and the Mimeta has the same character, although it is not a 

 common one in the genus. The result is, that on a super- 

 ficial examination the birds are identical, although they have 

 important structural differences, and cannot be placed near 

 each other in any natural arrangement. As a proof that the 

 resemblance is really deceptive, it may be mentioned that the 

 Mimeta is figured and described as a honeysucker in the costly 

 Voyage de I' Astrolabe, under the name of Philedon bouruensis ! 

 Passing to the island of Ceram, we find allied species of 

 both genera. The Tropidorhynchus subcornutus is of an earthy 

 brown colour washed with yellow ochre, with bare orbits, 

 dusky cheeks, and the usual pale recurved nape-ruff. The 

 Mimeta forsteni is absolutely identical in the tints of every 

 part of the body, the details of which are imitated in the 

 same manner as in the Bouru birds already described. In 

 two other islands there is an approximation towards mimicry, 

 although it is not so perfect as in the two preceding cases. 

 In Timor the Tropidorhynchus timoriensis is of the usual 

 earthy brown above, with the nape-ruff very prominent, the 

 cheeks black, the throat nearly white, and the whole under 

 surface pale whitish brown. These various tints are all well 

 reproduced in Mimeta virescens, the chief want of exact imita- 

 tion being that the throat and breast of the Tropidorhynchus 



