301 Mr. G. Talbot on Life-history of Stick Insect. 



insects lias rendered possible their protective coloration 

 and instincts. This may be ancestral to the parthenogenetic 

 condition, which would seem to have been developed in 

 response to continued competition. This would suggest 

 that the immunity obtained through instinct and coloration 

 was at some ]jeriod weakened by the introduction of another 

 destructive factor in the environment. 



20. Inheritance of Variability. 

 Tn the various factors dealt with in the preceding tables, 

 the oft'spring may differ widely from the ])arent in one or 

 two generations. Neither do the individuals of one genera- 

 tion exhibit any agreement in these factors, except in the 

 case of size, which is fairly constant throughout, and 

 probably of specific peculiarity. 



July 26, 1920. 



