The little caterpillars emerge in about a week, and then comes the process of eating until they grow into the large, green tomato or tobacco worms that all of us have seen. When hatched the caterpillars are green, and have grey caudal horns similar to Lineata. After eating for four or five days, they cast their skins. This process is repeated three or four times, when the full-grown caterpillars are over four inches long, exactly the colour of a green tomato, with pale blue and yellow markings of beautiful shades, the horns blue-black; and appearing sharp enough to inflict a severe wound.

Like all sphinx caterpillars Celeus is perfectly harmless; but this horn, in connexion with the habit the creatures have of clinging to the vines with the back feet, raising the head and striking from side to side, makes people very sure they can bite or sting, or inflict some serious hurt. So very vigorous are they in self-defence when disturbed, that robins and cuckoos are the only birds I ever have seen brave enough to pick them until the caterpillars loosen their hold and drop to the ground, where they are eaten with evident relish.