Bau — Longevity in Saturniid Moths. 77 



lated by natural selection for the good of the species, con- 

 serving the time which is an advantage to the race and 

 curtailing useless existence. 



In short, we must conclude that the longer or shorter 

 life of these insects is due to physiological processes, but 

 one must also admit that, regulating these physiological 

 processes in some way, we have at work natural selection 

 carefully seeing that these insects with aborted mouth 

 parts have all of their ova at hand ready for ovipositing 

 when they emerge from the cocoon, in addition to the 

 proper amount of nutriment to give them sufficient length 

 of life to "deposit them, and this even though we know 

 not whether the aborted mouth parts are due to the re- 

 serve nutriment or the reserve nutriment is there be- 

 cause of the aborted mouth parts. 



Hence it would seem that our major problem is one 

 not of physiological phenomena alone, nor of heredity 

 of longevity alone, but a complex blending of these two 

 factors such as can be raveled only by the analysis of 

 large quantities of data on varied material. 



