196 



COLORATION IN LEPTINOTARSA. 

 Table 88. Temperature and humidity conditions. 



* Dew. 



In these experiments 19 per cent died in the larval stage, 11 per cent in the 

 pupal, and 70 per cent, equally divided as to sex, emerged as imagines. The 

 larval stage was shortened on the average 4 days and the pupal x l / 2 days. 



The larvae were large and well nourished, being 5 per cent above the nor- 

 mal in size and 7 per cent above in weight. Their hypodermal color was a 

 deep wine-red, with all dark markings a brilliant black. The imagines were 

 also strong and active, being 6 per cent above the normal in size. Their 

 colors were also dark, the hypodermal color being chrome yellow, often with 

 a distinct reddish tinge. All areas of cuticula pigment were well developed 

 and fusions were frequent. The general appearance of the beetles was 

 melanic, the mode of the entire series being strongly toward the melanic end 

 of the color range, as may be seen in the following table : 



Table 89. 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. . +6 



Experiment 24. To determine the effects of a considerably increased average deviation 

 of both temperature and moisture upon the color and color pattern of L. decemlineata. 



Conditions. Temperature on the average 10.6 C. and relative humidity 

 21 per cent above that in nature, with other conditions normal. 



Apparatus. The same as in experiment 23. 



In the experiments of this series, which also covered the years 1899 to 1904, 

 2,000 larvae hatched from 3,600 eggs were reared under the following condi- 

 tions of experiment : 



