2. That two natural colors, madder-lake and indigo, can be produced artificially by the influence of acid on fat-bodies. 3. As protein bodies in insects are changed into fat-bodies, and may be changed by acids contained in insects into fat-acids, the formation of colors in the same manner seems probable. 4. That colors can be changed by different temperatures. 5. That the pattern is originated probably by a combination of oxygen with the integument. 6. That mimicry of the hypodermal colors may be effected by a kind of photographic process. 7. Finally, color and pattern are produced by physiological processes in the interior of the bodies of insects. Krukenberg concludes that change of color (in perfectly developed insects) is a consequence of the change of food, and can be explained by the alteration of the pigment through heat and light. His experiments were made in order to ascertain the cause of the turning of green grasshoppers in autumn into yellow and pink. He tried to answer two questions: First, does the pigment of grasshoppers originate directly out of the food, and does it consist of pure chlorophyll or of a substance containing chlorophyll, or is it to be accepted as a peculiar product of the organism? Second, is the color the consequence of only one pigment, or of several? Special analysis proves that the green color has no connection with chlorophyll. He concludes: “It is evident that the green color of the grasshopper is the consequence of several different pigments which can be separated by a chemical process.” Krukenberg believes that light has a marked influence on the color of insects and that light turns to red or pink the insects which were green during the summer. It would seem, however, more probable that cold was the agent, the change being due to the colder autumn weather. Here we might refer to the results of the studies of Buckton and Sorby, on the changes in color of Aphides:— “1. The purple coloring matter appears to be a quasi-living principle, and not a product of a subsequent chemical oxidizing process. Mounted in balsam or other preserving fluids, the darker species stain the fluid a fine violet. “2. As autumn approaches and cold weather reduces the activity of the Aphides, the lively greens and yellows commonly become converted into ferruginous red, and even dark brown, which last hue in reality partakes more or less of intense violet or purple. These changes have some analogy with the brilliant hues assumed by maple and other leaves during the process of slow decay. “3. Aqueous solutions of crushed dark brown and yellow-green varieties of Aphides originate different colors with acids and alkalies.