“Oh, and the eggs have hatched too,” said Tom. “Look at them now, Uncle George!” His uncle looked, and saw that the white patches of eggs had given place to larger patches of little active, dark coloured maggots. “We want to know what has become of the lovely carved shells of the eggs,” said Tom. “They have been eaten up,” his uncle replied. “From the moment a caterpillar is born he does nothing but eat—eat—eat. He begins by eating the shell of the egg he comes out of. “For the first week of their lives these tiny caterpillars feed together in small bands, and they grow so fast you can almost fancy you see them growing. After they have grown to a certain size, each caterpillar starts out for himself.” “Do you see the three butterflies that have hatched out?” asked Tom. “Yes, I see them. There are two females and one male,” said Uncle George. “How can you tell males from females?” asked Frank. “Oh, that is easy enough,” Uncle George replied. “The females are larger, and have two big black spots on each of their front wings. But I only see eight of the large cabbage caterpillars. We put in twelve, I think.” “Look!” said Frank, pointing to the roof of the cage. “Ah, yes, I see them. Two of them have passed into the pupæ stage, and are slung up by their silken belts to the wall of the cage. “The other two are spinning silken belts round the middle of their bodies, if they have not already done so. After this belt is finished they will slowly slip their useless green skins off, and finally get rid of them by sharply jerking the tail end of their pupa cases.” “Yes, we watched those other two do that,” said Tom. “Notice,” continued Uncle George, “that all your big cabbage caterpillars have lost their yellow stripes and are now of a bluish green colour. They have stopped feeding, and are now dull and sleepy. This indicates that they are about to enter the pupa stage.” “But look at the currant and the hairy caterpillars, uncle,” said Frank. “My dear boy,” said Frank’s mother, “Uncle George must really have food and rest after his long journey. He will hear about the other caterpillars some other time.” Exercises on Lesson XIII. 1. Explain why the pupæ of white butterflies are coloured like the objects they are attached to. 2. Write the life of a white butterfly, and illustrate your description with sketches of caterpillar, pupa, and butterfly. 3. The life of an insect is divided into four distinct stages. Name them. Which is the longest stage in the case of the white butterfly? 4. Describe, as you have observed it, the behaviour of a caterpillar as it passes from the larva to the chrysalis form. XIV.—THE TOILING CADDIS. “Look here, boys,” said Uncle George, “you have been paying nearly all your attention to the larva cage during my absence, and have forgotten the caddis worms.” [Illustration]