(4) 



and form a very deep cnp, like nests of other Heed-warblers. They are, however, 

 evidently Dot hanging up on reeds or twigs, like those of onr Acrocephali. 

 The eggs are white, covered with darker and lighter brown patches and smaller 

 spots, and underlying ashy grey or lavender-grey spots. These spots are generally 

 thicker near the broad end, sometimes forming a loose ring, and they are some- 

 times eqnallv spread over the whole surface. Four dozens measure: 24:15-7, 

 23:16, 25-2": 18, 21-5: 10-2, 22o : lo-9, 21-5: 16-2, 2]-5:10-l, 21-o : 15-7, 24:15, 

 22-5: 16-4, 23:16, 22:15-1, 22-5:15-7, 22:16, 23:16, 225 : 16-5, 22-5:16-6, 

 22-5: 15-5, 22:16, 205:17, 21:161, 22:16-1, 20-7:161, 23:15-6, 22:21-5, 

 23 : 16, 21-6 : 16.3 mm., and so on. Nehrkorn, Kat. Eiersamml., p. 33, gives 

 21 — 23 : 15 mm., and mentions the whitish (instead of greenish) ground-colour. 



5. Metabolus rugensis Hombr. & Jacq. 



(Wiglesworth No. 71, p. 19 ; Cat. B. Brit. Mus. IV. p. 238 ; Finsch, 

 P.Z.S. 1880 p. 575.) 



The extraordinary sexual dimorphism in the colouration of this bird, and the 

 colour of their young has not been fully understood. In the Catalogue of Birds 

 (IV. p. 238), the adult 7nale is correctly described as white with black throat 

 and forehead, and partly blackish shafts to the rectrices and remiges. The adult 

 female, however, is not correctly described in that work. What is described there 

 as the adult female is evidently a young female changing to the adult dress. 



The admixture of white on the abdomen and under tail-coverts in that description 

 is somewhat peculiar, but the description is made from Hombron and .Jacquinot's 

 figure, in which the white is accidental or an addition of the artist. The aAwM female 

 is quite sooty black all over. This was evidently known to Dr. Finsch, for {P.Z.S. 

 1880 p. 575) he says : " Young females change from the cinnamon into the black 

 garb." This same author, however, was of opinion that the adult male changes 

 into a sooty black plumage in August, while in July they are still in full white 

 dress. He says, after describing the adult male : " In August the same birds 

 are of a uniform dull sooty black." Such is not the case, but the black birds 

 are the adult females only, while young birds are of a cinnamon colour, paler 

 and almost white below. E.Kamples changing from the cinnamon dress to both 

 the white of the adult male and the black of the adult female, were obtained in 

 December, bnt some also in November and January, and one in June. 



The plumages of this bird may thus be briefly diagnosed : 



White with black throat and forehead : cj ad. 



Uniform sooty black : ? ad. 



Cinnamon : S and ? juv. 



Mixed cinnamon and white : S hab. trans. 



Mixed cinnamon and black : ? hab. trans. 



The birds in transitional plumages are remarkable in many ways. Although 

 they are, of course, passing through a moult, there are males in evidently cleanly 

 moulted jilnmage with a great amount of cinnamon to the feathers, especially their 

 tips and outer webs. The question now arises, and cannot be settled by me at 

 present, whether these individuals retain this cinnamon colour until the next 

 moult, or whether it is lost before— in the latter case we would have to accept 

 a change of colouration without moult. I may remark that the usual abrasion 

 cannot produce this change, as there is too much cinnamon in the plumage. In 



