1 7 6 



COLORATION IN LEPTINOTARSA. 



8,861 imagines. These beetles were subjected to conditions of temperature 

 such as might be produced in nature by the coming on of a cold or hot spell 

 when the larva? were about to pupate, and the continuance thereof during the 

 pupal period. Such cold or hot spells do occur frequently in nature, and are 

 productive of modifications in the coloration of animals and plants. These 

 experiments show what would happen in the way of modified color or color 

 patterns if by accident or intentionally a lot of nearly grown larvae were to be 

 transported from, let us say, the average conditions of the northeastern United 



.Experiments with temperatures above the normal. 



..Experiments with temperatures below the normal. 



Text-figure ii. Diagrammatic representation of the results obtained in experiments i to 7, showing 

 in both high and low temperature experiments the production of metallic conditions by the first devia - 

 tion followed by the production of albinic tendencies as the temperature is further increased or 

 decreased. The heavy line across the middle of the figure on class 9 is the modal class of the 

 parents above and below which the tendency is metallic and albinic, respectively. The deviations in 

 temperature are given in degrees centigrade. 



States to Arizona or New Mexico (experiments i and 2), or to the Yuma 

 Desert (experiment 3), to Nova Scotia or Newfoundland (experiment 4), or 

 to Labrador (experiments 5, 6, and 7). 



The general results derived from these experiments have been put into the 

 form of a table in text-figure II. In this figure the high-temperature experi- 

 ments are represented by the solid lines and the low by the broken lines. In 

 both sets of experiments the result produced by either a higher or a lower 

 temperature is the development of a greater amount of pigmentation and a 



