MODIFICATION OF COLOR. 

 Table 48. Temperature conditions. 



171 



In these experiments 95 per cent died in the last larval stage, especially in 

 the prepupal period, 4 per cent in the pupal period, and 1 per cent appeared 

 as imagines. These latter were equally divided as regards sex, and were 

 39 per cent below the average in size. The hypodermal color was pale 

 yellowish-white, without a trace of lipochrome pigments, and the cuticula 

 color was much reduced. On the epicranium all spots were completely 

 absent ; while on the pronotum b, d, f, and e were absent, c was very small, 

 and a was divided into two spots, the anterior and posterior. On the elytra 

 the costal, anal, and cubital stripes were either wanting or very rudimentary, 

 while the others were reduced in size and were light brown in color. Upon 

 the ventral surface the legs had no dark color and all spots were reduced, 

 excepting the outer sternals, which were represented by the merest traces 

 upon the thoracic and first two abdominal segments. The general color of 

 these beetles is shown in the following table : 



Empirical mode of parents 9 



Empirical mode of control 10 



Empirical mode in experiment . . 3 



Modal deviation of parents o 



Modal deviation of control' +1 



Modal deviation in experiment . 6 



In experiment 3 the limit is almost reached of the average deviation of tem- 

 perature to which it is possible to subject these insects without their being 

 previously adapted to a higher temperature, an average increase of i C. 

 above the condition of experiment 3 resulting in a mortality of 100 per cent. 



Experiment 4. To determine the effect of a slightly lowered average temperature upon 

 the color and color pattern of L. undecimlineata. 



Conditions. Temperature on an average 6.5 C. below that in nature. 

 Other conditions normal. 



Apparatus. Special breeding tanks with inner and outer glass walls, be- 

 tween which there were 2 l /i to 3 inches of constantly changing cooled water. 

 Ice boxes were also used. 



