MODIFICATION OP COLOR. 



I8 5 



Experiment 14. To determine the effect upon adult coloration of L. decemlineata of a 

 considerable increase in average temperature applied throughout the larval stage only. 



Conditions. Temperature on the average 14.5 C. above that in nature, 

 with other conditions normal. 



Apparatus. The same as in experiment 10. 



In this experiment 2,000 larvae were used, hatched from 3,300 eggs which 

 were taken at random soon after being laid, and placed in the conditions 

 of the experiment. The larvae were kept there until time for pupation that 

 is, until the beginning of the prepupal period when they were returned to 

 normal surroundings. The temperature records are as follows: 



In this experiment, which is an exact duplicate of experiment 10 as far as 

 the larvae are concerned, the mortality was approximately the same in the 

 larval stage, but lower in the pupal that is, 60 per cent died in the larval 

 stage, 10 per cent in the pupal, and 30 per cent appeared as imagines. The 

 imagines were normal, as is apparent in the following table : 



Table 71. General color of beetles used. 



Empirical mode of parents 9 



Empirical mode of control 9 



Empirical mode in experiment ... 9 



Modal deviation of parents o 



Modal deviation of control ....... o 



Modal deviation in experiment. . . o 



Experiment 15. To determine the effect upon adult coloration of L. decemlineata of a con- 

 siderable average decrease in temperature when applied throughout the larval stage only. 



Conditions. Temperature on the average 12 C. below that in nature, 

 with conditions as in experiment 10. 



Apparatus. The same as in experiment 10. 



In this experiment, from 3,100 eggs were obtained 1,500 larvae, which were 

 kept in the conditions of the experiment until the beginning of the prepupal 

 period, and were then returned to a normal environment. 



