134 



The Mechanism of Evolution in Lbptinotaesa 



This set of conditions is rigorous and serves to stimulate or to accelerate dif- 

 ferent agents and operations in the two lines. When the cross is made between 

 the pure and the suspected materials, F^ shows no trace of the signaticollis 

 conditions at any point, nor does it appear in Pj unless the same set of condi- 



F4 



Fj. 



F, 



=J 



1 E 



S S 



II 



8 8 8 8 



o u) o 



L, undecimlineata. L. signaticollis. 

 Fia. 9. 



tions are applied to the breediag pairs of the two at the time of breeding ; and- 

 moreover, the result is not produced unless the same complex is applied to the- 

 Fj. The mated pairs ready for breeding are introduced into the apparatus 

 under the conditions and allowed to remain there until the eggs are deposited,,. 



