574 MIMICRY 
of black feathers, and even the protuberance on the bill of the 
Philemon being imitated by a similar enlargement of that of the 
Mimeta. In the same way Mr. H. O. Forbes in Timor Laut found 
a corresponding species of Philemon and one of Mimeta so closely 
alike that Mr. Sclater did not at first distinguish one from the other 
(Proc. Zool. Soc. 1883, p. 199). In these cases it is pretty clear 
that the Mimeta, which retains the dull coloration now characteristic 
only of the immature among the Oriolidx,! is rightly named the 
mimic, since it is a comparatively weak bird, and must benefit by 
being mistaken for the strong, pugnacious and noisy Philemon, two 
or three of which will drive away Crows and even Hawks that 
venture to perch on a tree they have occupied.? 
On the information of Mr. Salvin, Mr. Wallace has cited 
(Contrib. Nat. Select. p. 107) another very curious case of Mimicry in 
Birds. This is furnished by Accipiter pileatus, a widely-ranging 
species of SPARROW-HAWK which near Rio Janeiro departs from 
the plumage it wears in other places to assume that of Harpagus 
diodon (HAWK), a local species of insectivorous habit, with the 
object, as suggested, of deluding small birds into the belief that it 
is harmless in character. The similarity here extends to both 
immature and adult plumages, which are very different. 
The most perfect case of resemblance between two Birds of 
different groups seems to be one that, though announced a good 
many years ago (Proc. Zool. Soc. 1870, p. 386), has been over- 
looked by most writers on the subject. This is exhibited in the 
genera T’ylas and Xenopirostris, peculiar to Madagascar,* the former 
being indeed of doubtful alliance, but generally admitted to be 
very near to Hypsipetes, which is placed either among the Turdidx 
(THRUSH) or Pycnonotide® (BABBLER), while Xenopirostris is one of 
the Laniide (SHRIKE), of which Family it wears the regular livery 
—though apparently dimorphically, for examples of X. polleni may 
be either white or buff beneath. But in either plumage this 
species is counterfeited, feather for feather, by Tylas eduardi, so 
exactly that but for a slight difference in size, and a marked dis- 
tinction in the bill and feet—both of which are in Xenopirostris 
1 Mr. Wallace speaks of Mimeta ‘‘ having lost the gay colouring” of Oriolus ; 
but I think the better way of stating the probability is as above. 
2 Mr. Wallace finding a peculiar Mimeta in Gilolo, hazarded the prediction 
that a corresponding Friar-bird would be found there, which subsequently proved 
to be correct (cf. Salvadori, Orn. Papuas. ii. p. 354). 
3 These species are rudely but recognizably figured, PZ. col. 205 and 198. 
4 Dr. Sharpe, it is true (Cat. B. Br, Mus. viii. p. 109), merges Mr. Elliot’s genus 
Clytorhynchus in Xenopirostris, making the range of the latter extend to New 
Caledonia. I venture to doubt the wisdom of this step. 
> By Dr. Sharpe (op. cit. vi. pp. 163-166) it is thrust into the bottomless pit, 
which he terms ‘‘ Zimeliidw.” THe recognizes 5 species of Tylas, M. Grandi- 
dier (Hist. Madag. Oiseaux, pp. 376-381) but one—with 3 local races, 
