i84 



COI.ORATION IN I.KPTINOTARSA. 



In this set of experiments (8 to 13), in which the beetles were subjected to 

 the conditions of the experiment throughout life, beginning a few hours after 

 fertilization, results were obtained in imaginal color modification that are 

 identical with those in experiments i to 7, where the beetles were used during 

 the late larval and pupal stages only. These results I have represented in 

 text-figure 12. Hence the conclusion to be drawn from these experiments is 

 that as far as adult coloration is concerned it makes no difference whether the 

 stimulus of increased or decreased temperature be applied for the entire life 

 or for the pupal stage only. That is, there does not appear to be any accu- 

 mulated effect of a temperature stimulus. 





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Text-figure 12.— To illustrate graphically the results obtained in experiments 8 to 13. 



It has been shown that the influence of high and low temperature upon the 

 larval color pattern is much the same as that upon the adult. Therefore it 

 would seem that the effect upon the color-enzyme forming cells at each period 

 of activity is immediate and persists only as long as the stimulus is applied, 

 and that there is no accumulated influence stored up through the larval period. 

 This has been conclusively shown by a set of experiments made to test this 

 point. In these experiments larvae reared up to the prepupal period under 

 the conditions of experiments i to 7 were at pupation placed in normal sur- 

 roundings. Now, if the effects of stimuli applied to the larvae were cumula- 

 tive, the fact ought to be apparent in the adults. Two experiments taken 

 from this set will serve to illustrate the results obtained from this entire series 

 of seven experiments. 



