RESEMBLANCES AMONG ANIMALS: 107 
strong, pugnacious, noisy, and very abundant Tropi- 
dorhynchus. ° 
My friend, Mr. Osbert Salvin, has given me another 
interesting case of bird mimicry. In the neighbour- 
‘hood of Rio Janeiro is found an insect-eating hawk 
(Harpagus diodon), and in the same district a bird- 
eating hawk (Accipiter pileatus) which closely re- 
sembles it. Both are of the same ashy tint beneath, 
with the thighs and under wing-coverts reddish brown, 
so that when on the wing and seen from below they 
are undistinguishable. The curious point, however, is 
that the Accipiter has*a much wider range than the 
Harpagus, and in the regions where the insect-eating 
species is not found it no longer resembles it, the under 
wing-coverts varying to white; thus indicating that 
the red-brown colour is kept true by its being useful 
to the Accipiter to be mistaken for the insect-eating 
species, which birds have learnt not to be afraid of. 
Mimiery among Mammals. 
Among the Mammalia the only case which may be 
true mimicry is that of the insectivorous genus Cla- 
dobates, found in the Malay countries, several species 
of which very closely resemble squirrels. The size is 
about the game, the long bushy tail is carried in the 
same way, and the colours are very similar. In this 
case the use of the resemblance must be to enable the 
Cladobates to approach the insects or small birds on 
which it feeds, under the disguise of the harmless fruit- 
eating squirrel. 
