no. 3633 ALLOXENIA — FRIEDMANN 5 



brown, and the few eggs of other coloration were regarded as unusual. 

 One of the latter, unmarked blue, is now to be considered as probably 

 misidentified Clamator jacobinus eggs. To the other types then de- 

 scribed may now be added still others, all suggesting a wide range 

 of coloration indeed although it is still apparent that the plain brown 

 egg outnumbers all the others many times over. 



The range of color variation may be seen in the following egg types : 



1. Plain chocolate brown to olive brown (the commonest type). 



2. Similar to no. 1 but paler, more pinkish, less chocolate, and slightly smaller 

 (Zululand, ex nest of Cossypha humeralis). 



3. Pale greenish white, thickly spotted with browns of several shades (Congo, 

 oviduct egg). 



4. Pale bluish green with an indistinct band of osbcure brownish spots at the 

 larger end (Kenya, ex nest of Cercotrichas leucophrys, according to Nehrkorn 

 1910, and ex nest of Saxicola torquata, both according to Schonwetter, 1964, p. 

 545). Pitman (1964, pp. 140-141) has described additional similar eggs: one, 

 from a Tchagra nest in Southern Rhodesia, was pale green with a few rusty- 

 brown spots, some very pale and small; another, from a Motacilla capensis nest 

 in South Africa, was pale greenish, heavily marked with shades of brown ". . . 

 and may link the previously described spotted or freckled egg with the well- 

 known normal type which is so profusely and finely marked as to appear almost 

 immaculate." 



5. Similar to no. 4 but olive green, flecked with strong reddish brown, espe- 

 cially at the larger end (ex nest of Cossypha caffra, no locality given, according to 

 Schonwetter, 1964, p. 545). 



6. Fawn brown with intense dark reddish-brown flecks (Schonwetter, 1964, 

 p. 545). 



7. Very pale green with very delicate pale-brown and grayish-violet flecks (ex 

 nest of Cercotrichas ruficauda [=C. leucophrys brunneiceps of our list], according 

 to Schonwetter, 1964, p. 545). 



8. Almost uniform grayish white, tinged with pale pink, with barely visible 

 scrawls (ex nest of Cossypha caffra, according to Schonwetter, 1964, p. 545). 



It should be mentioned that Schonwetter (1964, p. 545) writes that 

 eggs of Cuculus solitarius are confused easily with those of Cossypha. 

 This cannot be correct, however, in nests of Cossypha caffra, the most 

 heavily parasitized species, whose eggs are whitish, freckled, especially 

 at the larger pole, with pale brown. There is much closer agreement 

 with the eggs of Cossypha natalensis and C. dichroa, an observation 

 first mentioned by Roberts (1940, pp. 139-140). As may be inferred 

 from the foregoing, there is less evidence than might have been ex- 

 pected for host egg mimicry in this cuckoo. The species of robin chats 

 to whose eggs the cuckoo's own are most similar are seldom used by 

 the parasite, whereas with no eggs of its frequent hosts do the cuckoos' 

 eggs bear such close resemblance as to be regarded as highly evolved 

 mimics in the same sense that some of the gentes of the European 

 cuckoo have become. Moreau (1949) thought there was some slight 

 adaptation in egg size by the red-chested cuckoo to the eggs of its 

 hosts, but this is not noticeable. 



