i6o 



Heredity and Eugenics 



*Dew. 



In this series of experiments 21 per cent died in the larval stage 

 and 9 per cent in the pupal, while 70 per cent appeared as imagines with 

 the proper color modifications. Throughout the whole series the 

 greatest care was taken to prevent the conditions of experiment from 

 having any possible influence upon the germ cells hi their growth periods 

 and during maturation and fertilization. This was accomplished by 

 removing the adults to normal conditions during the period of germ- 

 cell growth and fertilization, the fertilized eggs being returned as soon 

 as laid to the conditions of exDeriment. 



.,._ Experiment 27*, Control 

 Generations Kept in Normal Conditions 



Experiment 273, Subjected 

 to Conditions of Experiment 



270'* 



FIG. 60. To show the different parts of an experiment, in which L 

 decemlineata was subjected to conditions which would modify the soma without 

 modifying the germ plasm. The generations underscored were subjected to the 

 conditions of the experiment; those not underscored were kept in natural 

 surroundings. 



