236 ON THE GENUS PYCNONOTUS 



at different times of the year by Sala and by van der 

 Keilen, I do not hesitate to declare both species as valid 

 and distinct, but frequently interbreeding in the hinter- 

 land of Mossaraedes and the Upper Cunene region. 



Besides five specimens from Mossamedes , unquestionably 

 belonging to P. nigricans, our Museum is in possession of 

 three individuals, collected by van der Keilen in the Up- 

 per Cunene region and erroneously mentioned in N. L. M. 

 1888, p. 228 and 1889, p. 196 as P. Layardi, which 

 represent as many different forms of hybridism. The first, 

 shot on Febr. 23'"'^ 1888, a female with black head , orange 

 eyelid and red iris , should make the impression of a true 

 P. nigricans , were it not for the white breast and abdo- 

 men , which is a characteristical of P. tricolor. 



The second specimen, a male, shot on Sept. 28^^ 1891, 

 resembles P. nigricans by its entirely black head and dirty 

 grayish white under surface , while by the black eyelids 

 and the dark brown iris it resembles P. tricolor. 



The third specimen, a female, shot on April 14^^ 1886 

 near Huilla, belongs to P. tricolor on account of its white 

 under surface , the black eyelid and brown iris , but the 

 head is blackish brown, much darker than in the two spe- 

 cimens from Bahr el Ghazal and for this reason may repre- 

 sent another form of hybridism. 



3. Pycnonotus Layardi. 



Pycnonotus Layardi Gurney, Ibis 1879, p. 390; Sharpe , Cat. B. VI, 

 p. 132 (1881). 



Hab. South Africa as far north as Lake Nyassa and 

 Damara Land. 



Two specimens from Port Natal. 



4. Pycnonotus nigricans. 



Pycnonotus nigricans (Vieill.) Gray, Gen. B. I , p. 237 (1847); Sharpe, 



Cat. B. VI, p. 134 (1881). 



Hab. South Africa, from Transvaal to Damara Laud, 

 extending north to the Quanza River. 



Notes from the Leyden ]Miiseiiui, "Vol. XVII. 



