AVIAN GENTJS CHRYSOCOCCYX 23 



result of this we see today in meyerii of the highlands of New Guinea. 

 This trend was continued in the development of the two species of 

 Asia, maculatus and xanthorhynchus, and, later, in that of the four 

 African species. However, between meyerii and the Asian and African 

 forms a new, important character arose, involving a remarkable 

 change in the pattern of the ventral plumage in the young. In all 

 the species from malayanus through meyerii, the young have the 

 mid ventral underparts unmarked, uniform, pale brownish or grayish; 

 in the young of the Asiatic and African species the underparts are 

 heavily crossbarred. From the early stock with this character two 

 species, maculatus and xanthorhynchus, evolved. In spite of their 

 external, visually great difference (green in the one and violet in 

 the other) they are closely related forms. 



At this point there is a great gap in the picture, the four African 

 species being quite different from the Asiatic and Australian ones, but 

 of these four, flavigularis and klaas seem not too distantly related to 

 maculatus, and, as we have seen, they possess so many characters in 

 common with cupreus that it becomes evident that they too are closer 

 together in their phylogeny than their very distinct plumage patterns 

 might suggest at first sight. Similarly, caprius, while differing in a 

 greater number of details from each of the other three African species 

 than they do from each other, is not more than another very distinct 

 species of the same genus, the ancient steps leading to which have long 

 since disappeared. 



On the whole, flavigularis and cupreus are largely sylvan in their 

 choice of habitat, klaas is more a bird of the open, tree-dotted busli- 

 veldt (although it does enter into the peripheral forest zones) , while 

 caprius is an open-country bird. The two Asiatic species, maculatus 

 and xanthorhynchus, and to a very large extent, klaas, are parasites on 

 sunbirds, while caprius is much more inclined to use the nests of a 

 great variety of weaverbirds as repositories for its eggs, although it 

 does utUize sunbirds as hosts at times, just as klaas occasionally para- 

 sitizes weavers. Nothing is known of the host choice of flavigularis; 

 those of cupreus include weavers, shrikes, flycatchers, warblers, wag- 

 tails, and sunbirds, a most heterogeneous assemblage. 



The external morphological characters most involved in the series 

 of changes are the following: 1. The degree of iridescence in the 

 plumage, which is only moderately well-developed in malayanus, 

 lucidus, basalis, and ruflcollis, almost entirely lost in osculans, and 

 highly developed in the remaining species, with its acme of develop- 

 ment in cupreus. 2. The amount and distribution of rufous coloration 

 m the tail feathers in the species forming the earlier part of the history 

 of the group — malayanus, lucidus, basalis, ruflcollis, and meyerii. 3. 

 The change from unmarked to a heavily barred ventral-plumage pat- 

 tern in the young; unmarked in malayanus, lucidus, basalis, osculans. 



