“Then they are expert botanists, I should say,” Jules remarked. “One might almost think so; at least they show in their choice so keen a discernment that often men of science go to school to them to learn the various degrees of relationship in the plant world.” “Oh, Uncle Paul, you are joking!” exclaimed Jules. “Joking? Listen. You know the nasturtium, that beautiful orange-colored flower ending at the bottom in a kind of horn; and you know the mignonette, that sweet-smelling plant that Mother Ambroisine grows in the window.” “Yes, I know them.” “Then tell me whether you find between mignonette, nasturtium, and cabbage any resemblance, any sign of plant-relationship.” “No, indeed! Those three plants are wholly unlike one another: their flowers haven’t the same shape, nor their leaves, nor yet their fruit.” “Well, my dear boy, you, who rather pride yourself on knowing something about flowers, really know much less about them than a poor little green caterpillar very common in our gardens; and many persons of far more learning than you could take lessons from this same caterpillar. It feeds indifferently on various cruciferæ, such as the cabbage, rape, and the turnip; but it also feeds on the nasturtium and the mignonette. Why? You must ask the scientists who make a thorough study of plants and are determined to find out the minutest details concerning them. They would tell you that there is something in their innermost structure, something invisible to our untrained eyes, that makes the nasturtium and the mignonette very nearly akin to the cruciferæ without looking like them. It is enough to puzzle anybody, I admit. A worthless caterpillar has, from the beginning of the world, eaten mignonette as well as turnip, cabbage as well as nasturtium, and has been familiar with plant-relationships unsuspected by science until our own time.” “I should like to see this caterpillar that knows so much about plants.” “Your desire shall be gratified without delay.” CHAPTER XLVI A DESTRUCTIVE FAMILY They went out to the garden and Uncle Paul hunted for some time in the cabbage bed before he found what he wanted. “Here is the caterpillar we were talking about,” he announced at last. “It is of a delicate green color with three yellow stripes running lengthwise. Now you must make the acquaintance of the butterfly. Jules, go and bring me the net.” Uncle Paul had a large gauze net, the mouth of which was attached to a hoop of coarse iron wire fastened to the end of a long stick. That was his butterfly-net, and in his leisure moments he used it for catching butterflies, that he might destroy them before they laid their eggs on the plants in the garden. The more butterflies destroyed, the fewer hundreds of caterpillars a little later. Jules came back with the net, but the chase did not accomplish the desired result, though another butterfly was caught very much like the one they were after.