74 U.S. NATIONAL MUSEUM BULLETIN 2 65 



cuckoo (9 instances out of a total of 62 cases of parasitism involving, 

 in all, some 41 species and subspecies of hosts). 



The measurements given in my earlier account (1949a, p. 121) were 

 based on two doubtful examples [ex nests of Colius and Amblyospiza) 

 and are too large. One egg, subsequently measured, was 20.5 X 13 

 mm. Schonwetter (1964, p. 587) gives the following size data (in mm.) : 

 length 17.8; Avidth 12.2; weight of the empty shell 0.06 grams; thick- 

 ness of shell 0.04 mm.; weight of the full egg 1.43 grams; relative 

 weight of shell to that of full egg 4.2 percent. 



There appear to be no differences between the eggs of the subspecies 

 of C. cupreus (eggs of intermedius and of sharpei known) . 



9. C. caprius: eggs polymorphic, five main types plus some variations 

 that do not agree very closely with any of these. The main morphs are: 

 1. unmarked white, stated by Schonwetter (ed. Meise, 1964, p. 567) to 

 be rare, but also reported by Priest (1948, pp. 47-48) and by Moreau 

 (1949, p. 535) ; recorded from nests of Parisoma subcaeruleum and 

 Ploceus velatus, Ploceus intermedius, Ploceus ocularis, and Euplectes 

 orix (Ottow and Duve, 1965, p. 435). 2. uniformly greenish-blue, a 

 common type frequently found in nests of Euplectes orix, the eggs of 

 which host are similar in color but usually smaller in size. In the 

 Transvaal R. A. Reed {in litt.) informed me that all caprius eggs he 

 found in nests of the red bishop {E. orix) were "quite indistinguishable 

 from those of the host, being a plain deep blue and of the same size 

 and shape as those of the host. ..." Again, G. Duve {in litt.), also 

 in the Transvaal, found only blue eggs of caprius with Euplectes orix, 

 no blue eggs of the parasite in the nests of the other common local 

 host, Ploceus velatus, with which only speckled cuckoo eggs were 

 found. A plain, blue caprius egg is known from a nest of the black- 

 chested Prinia, P.flavicans, found close to a nesting colony of Euplec- 

 tes orix. It is possible that this egg was deposited by a didric otherwise 

 parasitic on the red bishops nearby. Ottow and Duve (1965) distin- 

 guish two types of unmarked blue eggs, a pale type which Duve found 

 in 3 nests of Ploceus capensis and in 7 of Euplectes orix near Johannes- 

 burg, and a darker type found by Duve in 13 nests of Euplectex orix 

 in the same area. 3. Pale green or cloudy white, sparsely splashed wdth 

 grayish and with grayish brown (referred to by Schonwetter as the 

 Ploceus velatus type), found mth similarly colored eggs of Ploceus 

 velatus but also with whitish eggs of Ploceus intermedius cabanisi, 

 and with greenish-blue eggs of Ploceus capensis oliva^eus. This is a 

 frequent egg morph of the didric cuckoo. Chapin (1939, p. 179) obtained 

 an oviduct egg of this type. 4. Background color varying from dull 

 white to fairly bright pale-green, blotched and speckled with coarse, 

 heavy, and, in some instances, dark-brown and grayish markings. This 

 type has been reported from nests of Passer melanurus, whose eggs 



