182 



COLORATION IN LEPTINOTARSA. 



In these experiments no color modifications were noticed in the larvae, but 

 the length of the larval life was prolonged 10 to 12 per cent. During the ex- 

 periment 21 per cent died in the larval stage, 15 per cent in the pupal, and 54 

 per cent emerged, of which 47 per cent were females and 53 per cent males. 

 The color modifications were almost exactly the same as those described for 

 experiment 5. The following seriations have been made to illustrate the gen- 

 eral color tendencies : 



Table 6s. General color of beetles used. 



Empirical mode of parents 9 



Empirical mode of control 9 



Empirical mode in experiment. . . 14 



Modal deviation of parents o 



Modal deviation of control o 



Modal deviation in experiment. . +5 



Experiment 12. To determine the effect of a considerable average reduction in temper- 

 ature upon the color and color pattern of L. decemlineata when applied throughout life. 



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

 other conditions normal. 



Apparatus. The same as in experiment 8. 



In these experiments, which were conducted during the years 1900 to 1904, 

 2,900 eggs were placed in the condition of the experiment, and from these 

 1,500 larvae were hatched. The temperature records are as follows: 



Table 66. Temperature conditions. 



In these experiments the hypodermal color of the larvae was duller than 

 normal, all the tergal and posterior basal pleural spots were dropped out, and 

 the legs, head, and pronotum were dark brown in color. During the experi- 

 ment 60 per cent died in the larval stage, 22 per cent in the pupal, and 12 per 

 cent appeared as imagines. These showed the same color modifications as 

 those described for experiment 5. Their seriations into color classes are as 

 shown in table 67. 



