28 MR. A. R. WALLACE ON THE BIRDS OF BOURU. [Jan. 13, 



other groups, especially Gallinaceae, — for example, Centropus pha- 

 aianus in Australia, and Carpococcyx radiatus in Borneo, which latter 

 is terrestrial in its habits, and much resembles the Euplocami of the 

 same island. Eudynamis also frequently resembles Pigeons, espe- 

 cially the females and young birds, which are banded like Macro' 

 pygia. Among the small Cuculinse some are very like Campephagce ; 

 and Chrysococcyx has put on the metallic plumage of Lamprotornis. 



Returning now to Mimeta and Tropidorhynchus, we have to ob- 

 serve that the former is a smaller, weaker, less active, less noisy, and 

 less pugnaciotis bird ; the feet have a less powerful grasp, and the 

 bill is less acute. The latter has a great variety of loud and piercing 

 notes, which bring its companions to the rescue in time of danger ; 

 and I have observed them drive away crows and even hawks which 

 had ventured to perch on a tree where two or three of them were 

 feeding. The Tropidorhynchus knows how to take care of himself, 

 and make himself both respected and feared ; it would therefore 

 evidently be to the advantage of the more defenceless Mimeta to be 

 mistaken for him. 



In this instance, as in most others, the imitation is far closer in 

 the living bird than in the dead specimens, and it is a far more satis- 

 factory case of mimicry than any of those which I have alluded to as 

 occurring among birds, and which are more or less general resem- 

 blances to another group ; while here we have two species, each con- 

 fined to a single island, and each accurately imitated by a bird of a 

 distinct family, with which it has no direct affinities. 



I therefore cannot doubt that this is a true case of mimicry, exactly 

 analogous to that so common among insects, and which my friend 

 Mr. Bates has the honour of having first brought under the same 

 general laws which have regulated all variation in the organic world. 



Criniger mysticalis. 



Viridi-olivaceus ; subtus Jlavo-virens ; gula crissoque Jlavescenti- 

 bus ; mento, loris et palpebris flavis ; remigum pogonio interna 

 fusco-nigro ; cauda immaculata. 



Entirely olive-green, more yellow-tinged beneath, especially on the 

 throat and under tail-coverts ; the lores, chin, and eyelids are pure 

 yellow, and also the basal half of the gape-bristles ; bill horny black ; 

 feet lead-colour ; iris red. 



Total length 9 inches ; wing 4-^ ; bill to gape 1 inch. 



Hab. Bouru. 



Remarks. — This species is nearest to Criniger simplex, from Gilolo 

 (Ibis, 1862, p. 350) ; but is at once distinguished by the markings 

 of the face and the remarkable half- yellow gape-bristles. 



Artamus leucogaster. 



Lanius leucogaster, Val. Ann. Mus. H. Nat. iv. t. 7. f. 2. 



Hab. Bouru and the whole archipelago, from Sumatra to New 

 Guinea. 



Remarks. — From the large specimens of N. Celebes to the small 

 ones of Timor and New Guinea there is such a gradation of size in 



I 



