Ill 



DIAGRAM OF VARIATION 



"81 



Phonygama atra 



Oriolus galbula 



Pica caudata 



2 :^" 



Semeioptera iuallacei 



iiij 

 I 



I 



I 



I I I 



1 1 • 



I.. 



Pyrrhocorax alpinus 



I I . 



Fig. 8. — Variation of Birds in Leyden Museum. 



