10 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



comparable to the slight morphological characters of the "host races" 

 described in some groups of insects and nematodes specific on diverse 

 plant hosts. As Mayr (1963, p. 458) has pointed out, these organisms 

 may concentrate upon specific hosts in one area but are able to 

 establish themselves equally well on others elsewhere. This is equally 

 true of the European cuckoo in areas that have experienced ecological 

 disturbances owing to agriculture or to other inroads of human 

 influence. 



An important point should be stressed. In the European cuckoo 

 we have good evidence of individual host specificity; in the African 

 species of Cuculus we have none. We only assume, with some reason 

 but not with any real evidence, that probably each hen lays all its 

 eggs in nests of a single species of host. If anything, the actuality of 

 alloxenia in these sympatric parasites argues for such individual host 

 constancy. 



Appendix: Source Data on Host Records 



Additional data on host records of the three African species are 

 appended herein for the benefit of readers of this paper who may other- 

 wise wonder where the records came from. Instances that are merely 

 additional and repetitive cases are not considered necessary to 

 describe but have been included in the enumeration given for each 

 host earlier in the paper. (See also: Bouet, 1961; Rorke, 1947; 

 Skead, 1951b.) 



Cuculus solitarius 



In the list of known hosts of the red-chested cuckoo given earlier 

 in this paper, some 14 kinds of birds are added to my earlier (1949a, 

 1949b, 1956) compilations of the fosters of this parasite. The data for 

 these additions as well as new records for little known but previously 

 recorded hosts are as follows: 



Tchagra species: Nest with a red-chested cuckoo egg found at Baragoi, Samburu 

 district, Kenya, by Pitman (1964, pp. 140-141). 



Andropadus virens virens: Listed as a host in Fernando Poo by Basilio (1963). 



Chlorocichla flaviventris centralis: Found to be parasitized in the Ngong region, 

 Kenya, by van Someren (1956, p. 154). 



Pinarornis plumosus: A parasitized nest reported from Northern Rhodesia by 

 Benson and Pitman (1956, pp. 37-38). Refers also to a second instance, from 

 Southern Rhodesia, collected by Plowes. Since then II. K. Brooke has sent me 

 two more Rhodesian records, one observed at Plumtree, Mar. 6, 1961, by C. J. 

 Vernon, and one by A. W. Wragg at the same place on Dec. 16, 1962. 



Cercotrichas barbata: One overlooked record from the Zimbiti district, Mozam- 

 bique, reported by Sheppard (1914, p. 3). If the subspecies rovumae should be 

 reinstated this host record would refer to that race. 



Alethe archeri: van Someren (in litt., May 14, 1961) informed me that his chief 

 collector Yokana found a young fledged red-chested cuckoo cared for by this 

 thrush in the Humia valley, west Ruwenzori, in 1946. 



