Fig. 74. — Photograph of demonstration case which has been arranged to 

 show the effects produced upon the progeny of a single pair of beetles by subjecting 

 the ova to strong incident physical forces, before and during fertilization. To the 

 left is represented the normal stock, showing no presence during the time of experi- 

 ment of the modified forms. The first two lots, A and B, were laid and matured 

 under normal conditions and gave normal types. Lot C, laid and matured under 

 the conditions of the experiment, gave part modified and part unmodified forms. 

 The same is true of Lots D and E. The modified types in this experiment were 

 mainly pallida, clearly distinguishable in the photograph by their lighter and 

 smaller form; they breed true in successive generations as indicated in the 

 demonstration case. 



