104 U.S. NATIONAL MUSEUM BULLETIN 265 



the thought of two or more species of parasites sharing the same 

 host species. 



From its original locus Chrysococcyx expanded its range south- 

 eastward to include Australia, Tasmania, New Zealand, and the 

 hio-hlands of New Guinea. From this area it moved westward into 

 northern Malaya, Burma, India, and southern China, and also to 

 Borneo and the Philippine Islands; later, from its Asiatic area of 

 occupancy, it progressed farther to the west and came to include 

 in its domain all of Africa south of the Sahara, although not the 

 islands of the Indian Ocean (Seychelles, Aldabras, Mauritius, Reunion, 

 Madagascar, the Comoros, etc.). Inasmuch as Madagascar became 

 separated from Africa in the Pliocene and inasmuch as no glossy 

 cuckoo occurs in that great island, it becomes necessary to postulate 

 a not earlier than Pliocene time for its westward spread, and, this, 

 in turn, implies a correspondingly earlier date of origin in the ancestral 

 homeland of the group. 



The evolutionary implications of the current distribution of the 

 species and subspecies of glossy cuckoos are discussed following their 

 listing in the appendix (pp. 111-113). 



Morphologically there are three groups of species within the genus. 

 The connections between the species of each group are obvious, 

 but those between the groups are conceivable only as inferences, since 

 the intermediate steps have long smce disappeared. What appears to 

 be the earliest group comprises the obviously closely related species, 

 malayanus, lucidus, basalis, rujicollis, and osculans, the last named 

 one being a little more distinct from the others than any of them are 

 from each other. Then, with a gap in a strict chronology of characters, 

 comes a second group including meyerii, maculatus , and xanthorhynchus. 

 Following this, with a still greater hiatus both geographically and 

 morphologically, comes the African group which includes Jlavigular is, 

 klaas, cupreus, and caprius. 



Similarly, in the development of irridescent, glittering plumage the 

 genus reveals a discordant, unchronological diversity, with great 

 development in meyerii in New Gumea, m maculatus and xanthor- 

 hynchus in southern Asia, and in cupreus in Africa, with a total loss 

 of this character in osculans of Australia and various degrees of in- 

 termediacy in malayanus, lucidus, basalis, ruficollis, jiavigularis, klaas, 

 and caprius. The genus differentiated into a dozen species, some with 

 numbers of races, but within these dozen entities no one discernible 

 progression of evolutionary trends can be found that parallels their 

 hypothecated phylogeny. Close similarities, both in morphology and 

 in ethology, exist between some of them, such as malayanus, lucidus, 

 and basalis or between maculatus and xanthorhynchus, while other 

 species, such as osculans and caprius, are unique extremes. 



