BIRDS OF ETHIOPIA AND KENYA COLONY 325 



One male, near Juja Farm, Athi River, Kenya Colony, August 

 20, 1912. 



Seven males and one female. Escarpment, 7,390 feet (2,200 meters), 

 Kenya Colony, September 4—9, 1912. 



Granvik ^* writes that he 'can not distinguish between this race 

 and jebelcnsis {ugandensis of his paper) but Hartert ^^ saj^s that the 

 series at Tring shows that Mkuyuensis is a much darker form. My 

 observations agree with those of Hartert except that I doubt that 

 the two forms are quite as well marked as Hartert's statement im- 

 plies. Long series show the differences in size and color to overlap 

 considerably. 



The total series of this race examined illustrates all the plumages 

 of this coly. 



Three nestlings are of interest because of the peculiar pterylosis 

 of mouse birds. The adults are commonly said to have no apteria 

 except one on the occiput, and anyone who has ever skinned a coly 

 has observed that there is no large bare area on the ventral surface 

 of the body as in almost all other birds. A very young nestling, 

 taken April 4 on the Tana River (F. R. Wulsin collection) shows not 

 only the occipital apterium, but also a pair of bare tracts, one on 

 each side of the throat, begiiniing ventral and caudal to the auri- 

 culars and extending diagonally dorsally and posteriorly and meet- 

 ing on the lower hind neck, separating the neck pteryla from the 

 spinal one, and then extending caudally for a short distance on either 

 side of the spinal pteryla, diverging laterally to their respective ter- 

 minations just posterior to the wings. In his great work on 

 pterylosis Nitzsch^" indicates these two apteria but does not bring 

 them together on the nape. His drawing shows the neck and spinal 

 pterylae to be continuous, which they are not. He also states that 

 colies have a simple (that is, not paired) ventral bare space entirely 

 confined to the hindmost part of the body, and surrounding the 

 anal opening. In his drawing, however, it is far too large, as it is 

 shown extending forward to the posterior end of the sternum. In 

 the three nestlings examined, this apterium is very small and narrow. 



The order of development of the first pennaceous feathering is as 

 follows. Apparently the remiges and rectrices sprout from their 

 sheaths about the same time as the dorsal body feathering and the 

 feathers of the crown. The flanks and thighs come in next, then the 

 ventral body plumage, then the forehead, cheeks, and nape, and 

 finally the feathers of the lores, chin, and throat. The entire body 



**Journ. f. Oinith., 1923, Soudeiheft, pp. 95-96. 



=®Nov. ZooL, vol. 31, 1924, p. 128. 



™ Edition by P. L. Sclater, Ray See, 18G7, p. 107, pi. 6, figs. 10 and 11. 



