Modification of Germinal Constitution of Organisms 183 



both directions, but out of them no new characters come 

 as the result of ordinary crossing. 



. In the first generation of this colony there was an 

 abundance of individuals of both sexes of the signaticollis 

 t\pe, and of the iindecimlineata type, and of a highly 

 variable intermediate hybrid type. A census was made of 

 the population on August 1 4 to 1 7 , with the following results : 



Signaticollis Type Mid-Type Undecimlineala Type 



4,518 11,744 5,091 



In this experiment, it was, of course, impossible to tell 

 from inspection whether the signaticollis individuals were 

 pure signaticollis, or pure signaticollis and a hybrid with the 

 signaticollis dominant, and the same was true with respect 

 to the Iindecimlineata. All of the beetles entered into 

 hibernation during the latter part of August and early in 

 September, 1904. The food plants survived the long, hard, 

 dry season and came up in the spring of 1905 in abundance, 

 and in June, 1905, individuals of all three types emerged 

 and were found to be interbreeding freely. A census made 

 of the individuals which emerged late in June gave the 

 following results: 



Signaticollis Type Mid-Type Undecimlineala Type 



1,027 1,744 478 



which clearly indicate that through some cause the hiber- 

 nating conditions of the location were favorable for signati- 

 collis, but decidedly unfavorable for the undecimlineata 

 and for the intermediate hybrid type. These individuals 

 were allowed to interbreed freely and produced a numerous 

 progeny, in which the larvae were of four different t\'pes: 

 white without spots, white with spots, yellow without 

 spots, yellow with spots. The second generation emerged 

 from the middle to the end of July, 1905, and showed a 



