2 3 



VAR I ATION 



Fig 19 



_ Fio. 19.— Some of the numerous variations in the pattern of the abdomen in the vellow- 

 jacket Wasp. rAfter KeUogg and Bell). 



VARIATION 

 Fig. 20 



Fig. 20.— " Mutations " or rapidly developinjj larpe inlieritable variations in Leptinotarsa 

 muUUtmiata. The type of the species i'2; and its extreme mutants rubieunda (I) and 

 melanothorax (3). (After W. L. Tower 



[Facing p. 76. 



