28 U.S. NATIONAL MUSEUM BULLETIN 22 3 



In this case, the correlation between the parasite and its presumed 

 common host, Estrilda senegala, is not as close as in the others men- 

 tioned. The latter (fig. 1, no. 5) has no tongue spots and only the 

 three large, anterior spots on the palate. 



Chapin (in litt.) examined a nestling Estrilda senegala at Richard 

 Toll, Senegal, and found that the tliree palatal spots showed a ten- 

 dency to fuse into a band, not shown in Neunzig's figure. What 

 material Neunzig may have used for his figure of V. chalybeata is not 

 known. I am not aware that anyone had a nestling of this bird for 

 examination at the tmie of his paper. 



In Steganura and its frequent host, Pytilia melba (fig. 1, no. 4), 

 the correlation is also given as close. The tlu"oat (not shown in the 

 diagram) is said to be pale rose pink \vath a fairly large pale-reddish- 

 violet spot on either side. In the middle of the palate is a single 

 round black spot. The margins of the bill are bluish white and are 

 said to be provided on the inner side with a small round black spot 

 (which does not show in figure 1). In P. afra the black palatal spot 

 is absent, but there is reason to think that it too serves as a host for 

 the paradise widow bird. As has been mentioned, Hoescli (1939, 

 p. 208) failed to find in his material from South- West Africa, the close 

 agreement that Neunzig described in mouth markings of Steganura 

 and Pytilia. 



While we may consider the problem of adaptive convergence 

 as one that existed more in the minds of its describers than in the 

 material that they were studying, the reflection tubercles are so 

 peculiar that a few words about them seem in order. They are 

 found only in the nestlings of the Viduinae and Estrildinae, and were 

 investigated primarily in one of the Australian estrildines, the Gould- 

 ian finch, Poephila gouldiae,^^ by A. G. Butler (1898), Lewek (1901), 

 Key (1901), and Brandes (1901), and especially by Chun (1902, 

 1903), and in Eryfhrura by Sarasin (1913). The structures were also 

 reviewed by Marshall (1913), IVIcAtee (1947) and Auber (1957). 

 Lewek stated that these structures glow in the dark, but he was 

 unable to determine whether this glow was due to an innate phos- 

 phorescence or was merely a concentrated reflection of light coming 

 from external sources. 



Chun's first studies, based only on examination of preserved ma- 

 terial, suggested that the tubercles might be true luminous organs, 

 but his later study of living nestling birds demonstrated otherwise. 

 Birds about 6 days old, with well developed gape tubercles were 

 placed in a photographic darkroom with only a little light entering 

 the room, and these organs definitely glowed, much as do the eyes of 



<' Amadina gouldiae Gould, The birds of Australia, pt. 15, 18'14, vol. 3, pi. 88 (Vlct^irla River, Northern 

 Territory, Australia). 



