VI CONTENTS. 



Color phenomena in insects — Continued. Page 



Development of coloration 124 



Purity of insect colors 124 



Evolution of the color patterns of insects , 125 



Laws of coloration ... 125 



Phylogeny of coloration 126 



Effect of environment upon coloration . 128 



Protective resemblance, warning coloration, mimicry 128 



The problems of insect coloration to-day 128 



The colors of the genus Leptinotarsa , 129 



Chemical or pigmental colors 129 



Physical or structural colors 131 



Chemico-physical or combination colors 131 



The development of colors in Leptinotarsa 132 



Chemical or pigmental colors 132 



Cuticula colors , 132 



The cuticula, its structure and composition 133 



Chemical examination of the cuticula colors 135 



Development of the cuticula colors 136 



Experiments pointing to the existence of enzyme action 137 



Hypodermal colors 140 



Chemical examination of the hypodermal colors 140 



Microscopical examination of hypodermal colors 141 



Development of hypodermal pigments 141 



Diffuse hypodermal pigments , 141 



Subhypodermal colors 142 



Physical colors 142 



Chemico-physical colors 142 



The ontogeny of color and color patterns 143 



In the larvae , . 143 



In the imagines 152 



The ontogeny of color on the epicranium and pronotum 152 



The ontogeny of color on the wings 154 



On the elytra 154 



On the hind wings 157 



The ontogeny of color on the abdominal and thoracic segments 157 



General aspects of color and color-pattern ontogeny. 158 



Localized stages in ontogeny of coloration , 163 



The experimental modification of color and color patterns 168 



Modification of color in L. decemlineata 168 



Temperature experiments 168 



Moisture experiments 188 



Experiments with temperature and moisture both variable 195 



Experiments in which temperature and relative humidity vary together 



in the same direction above or below the normal 195 



Experiments in which L. decemlineata was reared during successive gen- 

 erations, with both temperature and moisture varying together, or 



in opposite directions above or below the normal 201 



Experiments with different foods 1 205 



Experiments with soils 206 



Experiments with light 208 



Experiments with atmospheric pressure 208 



