2 3 



VAR I AT! ON 



Fig.19. 



FIG. 19. Some of the numerous variations in the pattern of the abdomen in the 

 yellow jacket Wasp. [Alter Kellog and Bell.] 



VAR IATION 



Ficf.20. 



PIG. 20.- " Mutations " or rapidly developing large inheritable variations in 

 LeptinotfArfM multitce-niata. The type of the species (2) and its extreme mutants 

 rubicunda (1) and melanothorax (3). [After W. L. Tower.] 



[Facing p. 76 



