CONTROL OF HEREDITY: EUGENICS 401 



they disappear. Very rarely a sudden 

 variation or mutation arises which is per- 

 petuated by heredity and which forms the 



Fig. 94. Common Colorado Potato Beetle, Leptinotarsa. 

 a, normal undecemlineata, b, the mutant augusto-vittata, c, the 

 mutant melanothorax, d, normal decemlineata, e, the mutant 

 tortuosa, f, the mutant defecto-punctata. (From Plate after 

 Tower.) 



