CTPSBLID^ CH^TUEA 29 



The tail varies a good deal in length. 



Distribution. — The type of this species was obtained in Nubia ; 

 it is spread over Africa to Senegambia in the west and through 

 east Africa as far south as the Zambesi and Damaraland. A 

 somewhat darker form separated as a sub-species {T. gracilis) 

 extends over the wooded districts of west Africa and is also 

 found in Madagascar. Within our limits the Palm Swift has 

 been obtained at Ondonga and Ovaquenyama in Damaraland by 

 Andersson, and on the Zambesi near Senna by Alexander. 



Habits. — This Palm Swift like the other species of the genus is 

 nearly always associated with palm trees. Alexander found a 

 colony of them on the Zambesi ; they had taken possession of the 

 palm trees, which grew near a village, around which they flew 

 incessantly. 



Heuglin (Orn. N. 0. Afr. p. 145), gives a good account of the 

 habits of this bird in the upper Nile valley ; he states that they 

 build their nests in the leaf sheaths or against the folds of the 

 downward hanging leaves of the " Dom" palms {Hyphene thebaica). 

 The nest is composed of wool and feathers held together by a sticky 

 secretion probably provided by the bird itself from its salivary 

 glands. They are untidy looking objects and sway about in the 

 wind; the cup of the nest is not very deep and it is difficult to 

 understand how the eggs are prevented from tumbling out. Brehm 

 suggests that they are glued by the secretion to the nest ; the eggs 

 are two in number, cylindrical in shape, rough in texture and of a 

 yellowish-white colour. In their other habits they resemble other 

 Swifts but they appear to be non-migratory birds. 



Genus III. CH^TURA. 



Type. 

 Chsetura, Stephens, Gen. Zool. xiii, pt. 2, p. 76 (1826) ...0. pelagica. 



Tarsi as long as the middle toe and claw, and unfeathered ; 

 the outer and middle toes with the normal number of phalanges ; 

 the toes arranged as in Cypselus -with regular intervals ; tail short 

 and even, the shafts of the feathers strongly stiffened and projecting 

 beyond the webs as prominent spinous points ; wings extending 

 far beyond the tail. 



The Spine-tails are widely spread from Amoor-Land throughout 

 Asia except in the west, Australia, Tropical Africa and the whole 

 of America ; one species just enters our limits on the Zambesi. 



