Expedition to the White Nile. 251 



keer, keer " — a complaining and almost squealing note. 

 They almost invariably perch on a low bough, from which 

 they every now and then dart to the ground, to seize and 

 devour some insect, and then return to their point of 

 observation. They also capture insects in the air and pick 

 them from the tree. 



Adult. Iris dark brown; bill dark horn-colour; legs and 

 feet black. 



Young. Iris, bill, legs, and feet dark brown. 



29. Lanius isabellinus Ehrenb. 



A pair of these birds was obtained near Kawa on April 8th. 

 We observed them nowhere else. 



Adult. Iris dark brown ; bill whitish at base, tip black ; 

 legs and feet black. 



30. Lanius dealbatus de Filippi. 



Lanius dealbatus de Filippi, Revue et Mag. Zool. 1853, 

 p. 289. 



Lanius leuconotus Brehm, Journal fiir Orn. ISSl', p. 147. 



My specimens agree perfectly with the type of Brehm's 

 L. leuconotus at Tring, as well as with the co-type of 

 L. dealbatus in the British Museum. This species was 

 nowhere common, but it was met with at most of our 

 camping-places. We once saw a pair, but the birds were 

 generally met with singly and were rathei- wild. 



Adult. Iris dark brown ; bill dark slate-colour ; legs and 

 feet blackish brown. 



31. NiLAUs AFER (Lath.). 



We only observed this bird between Jebel Auli and 

 Gerazi, from 25 to 60 miles south of Khartum. In that 

 district it was not uncommon. This was one of the few 

 species found breeding. The sexual organs in the specimens 

 preserved were in an advanced condition, and I watched a 

 pair building a nest on May 1st. It was placed in the fork 

 of a horizontal bough about 30 feet up a sont-tree in a thick 

 wood. Both birds worked at building, bringing material at 

 intervals of a minute, and often less, during the considerable 

 time I watched them. They invariably sat in the nest and 



