Fruit Flies 



The two uj)per figures show the male (right) and female (left) of the 

 fryit fly. The six lower figures show some of its 200 ami uiore muta- 

 tions, some of the most striking of which are shown by the wings. 

 Note the wingless individual in the lower riglitliand corner, and the 

 one with asymmetrical wings just above. By their extensive studies of 

 this humble insect, Professor Morgan and his students have added vastly 

 to our knowledge of tlie laws of inheritance, which luild true not only for 

 lower animals, but for num himself. After Morgan, "Heredity and 

 Sex, ' ' 



By permlf:xion of the Cohimhia Univcrk-iii/ Press. 



212 



