On the European Cuckoo and its Indian Allies. 355 



its darker and brownish-olive upper parts, crossed by broad 

 and wavy dusky markings and by narrow wavy markings of 

 yellow ; the spotting upon the wing-coverts less distinct ; 

 the under surface of the body very much less yellow. Total 

 length 3'5 inches, culmen 0*4, wing 2"1, tail I'l, tarsus 0"5. 



$ . Differs from the male in having the forehead and 

 crown like the occiput and nape, black, spotted with pure 

 white. 



The types are in my collection, the male being from Ro- 

 raima, British Guiana, 5000 feet, Aug. 20 {H. Whitely) ; the 

 female from Camacusa, May 3rd {H. Whitely). 



XXXV. — On the European Cuckoo and its Indian Allies. 

 By Eugene W. Gates, F.Z.S. 



The three allied species of Cuckoos which inhabit the Indian 

 Empire have hitherto been considered separable only on the 

 ground of size, and two of them, those most closely allied 

 to each other, further on the score of their having different 

 notes. 



My object in writing the following is to show that their 

 separation rests on a better and a more satisfactory basis 

 than that of size and the practically useless character which 

 a vocal note affords. 



This basis is that of the plumage of the young, which differs 

 conspicuously in each species and affords conclusive evidence 

 that the three birds are quite distinct ab ovo. 



All the Cuckoos of the Cuculus canorus type have the 

 plumage of the young very complex. There is no evidence 

 whatever to show that the young Cuckoo moults either in the 

 first autumn or in the following spring ; and the evidence on 

 the other hand is overwhelming that from the nestling-stage 

 to the adult plumage the change is effected by a continual 

 and never-ceasing alteration in the colour of the feathers. 

 These changes are systematic and subject to rule in each 

 species ; but owing to individual temperaments hardly two 

 young birds will ever be found to be exactly alike. But the 



