Chap. XVI. CLASSES OF CASES. 187 



RULES OR CLASSES OF CASES. 



I. When the adult male is more beautiful or con- 

 spicuous than the adult female, the young of both sexes 

 in their first plumage closely resemble the adult female, 

 as with the common fowl and peacock ; or, as occasion- 

 ally occm's, they resemble her much more closely than 

 they do the adult male. 



II. When the adult female is more conspicuous than 

 the adult male, as sometimes though rarely occurs, the 

 young of both sexes in their first plumage resemble 

 the adult male. 



III. When the adult male resembles the adult female, 

 the young of both sexes have a peculiar first plumage 

 of their own, as with the robin. 



lY. When the adult male resembles the adult female, 

 the young of both sexes in their first plumage resemble 

 the adults, as with the kingfisher, many parrots, crows, 

 hedge-warblers. 



Y. When the adults of both sexes have a distinct 

 winter and summer plumage, whether or not the male 

 differs from the female, the young resemble the adults 

 of both sexes in their winter dress, or much more rarely 

 in their summer dress, or they resemble the females 

 alone ; or the young may have an intermediate cha- 

 racter ; or again they may differ greatly from the adults 

 in both their seasonal plumages. 



YI. In some few cases the young in their first plumage 

 differ from each other according to sex; the young 

 males resembling more or less closely the adult males, 

 and the young females more or less closely the adult 

 females. 



Class I. — In this class, the young of both sexes 

 resemble, more or less closely, the adult female, whilst 

 the adult male differs, often in the most conspicuous 



