Poecilomeres 



" On the other hand, among many species the 

 differentiation of colour on the pcecilomeres is 

 not so conspicuous as to attract the eye or to 

 serve in any way for protection or mimicry, yet 

 we still find them marked by differences of colour 

 so slight that, unless especially looked for, they 

 would never be noticed. 



"Or, again, some species occasionally, but not 

 invariably, show a few white feathers on certain 

 parts of their body, and, when such is the case, 

 it will be found that these white feathers appear 

 on the pcecilomeres. . . . There is hardly a 

 species in which examples of these pcecilomeres 

 may not be found. . . . The Kingfisher (Alcedo 

 ispida] shows the various head pcecilomeres very 

 clearly, and as examples of inconspicuous differ- 

 ences on these tracts, the rump of the hen sparrow 

 (Passer domesticus] and hen chaffinch (Fringilla 

 ccelebs), the malar stripe and dark ear-patch of 

 the hen Yellow Bunting (Emberiza citrinella), 

 and the dark ante-orbital patch of the Barn Owl 

 (Strix flammea) are familiar examples. And, 

 lastly, as an instance of the class where a few 

 white feathers frequently, but not invariably, 

 appear, the young of the cuckoo (Cuculus cano- 

 rus) forms a good example. 



" These spots may, however, appear in a tran- 

 sitory manner, as, for instance, where a change 

 of plumage (not necessarily moult) is occcurring." 



As an instance of this, Bonhote cites the case 

 T 289 



