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 varjdng 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. 



Mimicry 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 same, 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. 



