i8o 



COLORATION IN LEPTINOTARSA. 



During this experiment there was a mortality of 55 per cent in the larvae 

 and of 30 per cent in the pupa:, 15 per cent emerging as imagines. These 

 were 35 per cent below the normal size and equally divided between the sexes. 

 The hypodermal color was pale yellow and the dark markings were much 

 altered. Upon the epicranium and pronotum the spots were small, and there 

 were no fusions. The epicranial spots h and ft' were wanting, as were also the 

 pronotal spots / and /' and often d and d', while b and V were much reduced 

 and a and a' were nearly divided into two spots each. In the larvae the 

 basal-pleural spots were lost in part of the larvae in the second instar, and the 

 tergal spots all disappeared. The cuticula pigments were also lighter, being 

 a dark brown. The general color tendency was albinic. as is shown in the 

 following seriations : 



Table 61. General color of beetles used. 



Empirical mode of parents 9 



Empirical mode of control 9 



Empirical mode in experiment ... 6 



Modal deviation of parents o 



Modal deviation of control o 



Modal deviation in experiment . 3 



Experiment 10. To determine the effect of a large average increase in temperature 

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



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

 with other factors normal. 



Apparatus. The same as in experiments 7 and 8. 



In this experiment 2,000 larvae hatched from 3,850 eggs were used. These 

 eggs were taken at random from potato plants soon after they were laid, and 

 were placed at once in the conditions of the experiment. The temperature 

 records are as follows : 



Table 62. Temperature conditions. 



