AVIAN GENTJS CHRYSOCOCCYX 21 



caprius. In the former species Hume (1875, p. 81) described an 

 immature bird from Upper Pegu Nnth the entire head, neck, chin, 

 and throat pale, rusty rufescent with broad blackish-brown streaks 

 and with the upper parts of the body hair brown. In the British 

 Museum collection I examined a young example of this species 

 (B.M. 82-1-20-989) from Thayetingo that had the entire head, 

 above and below, cinnamon with longitudinal blackish streaks, 

 reminiscent of Cacomantis. In the didric cuckoo the hepatic phase 

 has been noted so far only in a few immature females. Such birds 

 are almost wholly bright cinnamon above on the head, nape, back, 

 wings, and tail ; the feathers of the back and wings and the upper tail 

 coverts have some greenish crossbars, and the rectrices, greenish- 

 black ones. 



In the case of still another glossy cuckoo, C. Haas, we find that 

 the females usually have some mixture of coppery-bronze on the top 

 of the head and the upperparts of the body and tail, but this varies, 

 apparently indi\idually. Whether this may be looked upon as a 

 vestigial or, conversely, as an incipient, hepatic morphism is not clear. 



It is necessary to stress that the term "plumage phase" is obviously 

 not the same in its implications in the cuckoos as in, for example, 

 the owis of the genus Otiis. In the latter birds the phase persists 

 throughout the life of the individual and not only for the duration 

 of its immature stage. 



The variable extent to which rufescent coloration normally occurs 

 in the tail feathers is a well-known character by which museum 

 taxonomers have long "keyed out" races and species of Australasian 

 glossy cuckoos. Thus, in C. malayanus we find the following racial 

 differences in this regard: some rufous on all the rectrices in rvssatns; 

 none or little on the outermost pair of rectrices but considerable on 

 the next three pairs in minutillus and poecilurus; none on the outer- 

 most pair but some on the next tw^o pairs in malayanus. In the related 

 species, C. lucidus, the nominate, New^ Zealand race and the New 

 Caledonian subspecies, harterti, have no or very little rufous on the 

 next to the outermost rectrix, while the south Australian and Tas- 

 manian race, plagosus, has a considerable amount of this color on 

 the inner w^eb of that feather. In the allied C. basalis the basal two- 

 thirds of all but the outermost and the median pair of rectrices are 

 rufous. The tendency to produce rufescent pigment in parts of the 

 rectrices appears also in the females of the African species, klaas and 

 caprius. 



The one place in the whole genus Chrysococcyx where the most 

 striking and most definite (invariable) production of this rufous 

 color has taken place is in the New^ Guinea highland species, C. 

 meyerii, in which the adult female has a bright-chestnut rufous patch 



