DIAGRAM OF VARIATION 



61 



Phony gam a air a 



Oriolus ga/bula 



Pica caudaia 





£ <*>. 



Semeioptera wallacei 



Pyrrhocorax alpinus 



luii 

 i 



i 



I i 



I Ii 



l.l 



i I i 



Fig. 8.— Variation of Birds in Levden Musenm. 



