Part 8

“But they are not both exactly alike,” said Frank, “I notice that one is smooth on the back, while the other’s back is all grooved.”

“You are right, Frank,” said Uncle George. “The one with the grooved wing-cases is the female. The one with the smooth cases is the male.

“Notice the long legs they have for swimming, and how they seem to oar themselves through the water. Notice also that the male has a large flat disc upon each of his fore legs. These are suckers, by which he can cling to things.”

“Why do they come up to the surface so often?” Frank asked.

“They cannot live without air. They carry a supply of air under their wing-cases. They just come up to renew it from time to time. This is done by thrusting the end of their bodies out of the water as you see.”

“One would think they ought to thrust their heads out to get air,” said Tom.

“That seems more natural to us, because we breathe with our mouths,” said Uncle George. “These animals take in air with their tails. A great many pond insects breathe in this curious way.”

“What do they feed upon?” Frank asked.

“They are fierce, greedy creatures,” his uncle replied. “They attack and kill worms, tadpoles, and even small fishes.”

Uncle George threw a small worm into the tank. One of the beetles seized it at once and began to devour it greedily. Presently the other beetle seized an end of the worm. The boys watched closely, and saw that the beetles’ jaws moved from side to side like a pair of pincers.

Next morning, when Uncle George and the boys went in to see the beetles, they found only one in the tank. The other had escaped during the night. After a careful search they found it, at the far end of the room, dead.

“Now, how do you think this beetle managed to get out of the tank and travel all that way?” Uncle George asked.

“It must have crawled up the inside of the tank, then down the outside. Then it must have fallen off the window-sill, and crawled right across the floor,” said Frank.

Uncle George shook his head.

“It might,” he said, “have managed to crawl up to the edge of the tank so long as its legs were wet. But as its long legs are made for swimming, and not for crawling with, I can hardly see how it could have crawled or walked all that distance.”

“Then how did it get there, Uncle George?”

In answer to Frank’s question, his uncle took the dead beetle, and placed it on a piece of paper on the table. He next moved aside each of the large black wing-cases with a pin.

Underneath these wing-cases the boys saw a pair of large wings neatly folded up. Uncle George removed one of the wing-cases, and unfolded one of the wings. Stretched out, it was longer than the beetle’s body, and it seemed to be made up of thin, clear skin, stretched on a framework of long, thin supports.

“Why, these beetles can fly,” said Tom.

“Of course they can,” said his uncle. “All beetles can fly. This creature has evidently been flying about the room all night. These insects are furnished with wings, so that they may be able to fly to another pool when food gets scarce, or when their pool dries up.”

Exercises on Lesson VI.

1. Would you keep water beetles, tadpoles, and stickle-backs together? Give your reasons. 2. Water beetles cannot live without air. Explain how they get it. 3. Compare the legs of a water beetle with those of any of our garden beetles. 4. Why are water beetles furnished with wings?

VII.—DAISIES.

While Uncle George and Frank and Tom were having a game of cricket, Dolly was amusing herself in another way. She had pulled a bunch of daisies and was joining them up into a daisy chain.

She finished her daisy chain just as her uncle and the boys finished their game.

“We will take some daisies home,” said Uncle George. He stooped down and dug out a whole daisy plant with his knife, while Dolly gathered a small bunch of the flowers. When they got home Uncle George placed his daisy plant in a saucer of water, and told the boys to bring out their magnifiers and sketch-books.

“First of all,” he said, “I want you to look at the daisy plant. Notice its leaves. Each leaf is broad at the end and narrow where it joins the plant. Notice also that the leaves all form a round green mat on the ground. Now, can you tell me what the leaf resembles in shape.”

1. Daisy Leaf. 2. Primrose Leaf. 3. Cowslip Leaf.