Puzzled by this, the children did look at their plates.
"But there's nothing left to look at," said Jack.
"That's just it. There's an old saying that people who eat all their
food make a clear day for the morrow. Now," he continued, "I'll smoke my
pipe of peace before we go on. Just look at that fellow darting about
over the pool!"
"Oh!" cried Betty, "it's a darning-needle, and it will sew up my mouth
and my eyes--oh, oh!"
"Nonsense, child, that's silly. The dragon-fly is a very useful and a
very harmless fellow. It's a pity that there are so many superstitions
about it."
"There's another name for it," said Jack--"devil's darning-needle."
"And in the South the darkies call it the mule-killer, and believe it
has power to bring snakes to life. It's all nonsense. They are not only
harmless to human beings but also very useful, for they eat flies and
mosquitoes at a great rate. Once upon a time I fed a dragon-fly forty
house flies in two hours. And they eat beetles and spiders and
centipedes. And sometimes they eat one another."
"Like the crickets?" said Betty.
"Yes, like the crickets. Just see that fellow dart about. The sharpest
sort of angles. There, it has something! It caught that lace-wing in its
leg-basket."
"Leg-basket!" exclaimed the children.
"Yes; it draws its six legs together, and makes a sort of basket right
under its head. Then the dragon-fly devours what it catches by these
strong-toothed jaws. It is a hungry fellow, it is."
The old man puffed away quietly for a few minutes, while the children
watched the darning-needle and hoped Ben Gile would say something soon.
"Those scientists," he continued, "who are working on flying-machines
could learn a good deal from this fellow. The dragon-fly is made for
flight. A long, slender, tapering body that cuts the air, moved by four
narrow, gauzy wings, and steered by that pointed abdomen. They eat,
mate, and lay their eggs while they are flying. I don't know that they
are still for more than a few seconds."
"Can you find their eggs?" asked Betty.
"Yes; their eggs are laid in the water or fastened to the stems of water
plants. See that damsel fly, the slender, smaller, pretty-colored
darning-needle? Well, it goes entirely under water, cuts a slit in the
stem with the sharp end of the abdomen, and lays the eggs in the groove
it has made. And they lay thousands of eggs."
"When they hatch out, what do they look like?" asked Jack, who grew
daily more interested in the creatures about him, and who, in the years
to come, was destined to be a great scientist.
"It looks a little like the mother," said Ben Gile, taking out his pipe,
"but not much. It goes through a great many changes before it is really
grown up. All told, the growth takes from a few months to a whole year.
The young one, called a nymph, is an ugly little fellow, dingy black
with six sprawling legs, two staring eyes, and a big lower lip which
covers up its cruel face like a mask. It is a true ogre, lurking under
stones and in rubbish at the bottom of the pond seeking whom it may
devour. It eats the smaller and weaker nymphs."
"Oh," said Betty, studying the picture the guide had drawn, "what an
ugly, ugly fellow!"
"It changes its skin a good many times, and sometimes it looks a little
better while the skin is still clean and light gray. But it soon turns
dingy again. See these three little leaf-shaped gills I've drawn?"
"They are like the screw on a steamer," commented Jimmie.
"They are, a little. Well, this chap uses these gills for the same
purpose as the steamer uses its screw--to scull through the water."
"What happens when it changes?" asked Jack.
"After the nymph has its full growth, some sunny morning soon after
daylight, it makes its way up out of the water on to a stem and waits
quietly for the old dark skin to split. Then out crawls a soft-skinned
creature with gauzy wings. But the body is so moist and weak it has to
wait awhile for the warm sunshine to harden the skin and strengthen the
muscle. When this is done the new dragon-fly, with its glistening body,
flies out from the pond in the bright, warm light."
"Then does it live forever?" asked Betty.
"No; it dies after twenty-five to forty-five days of its flight. Here,
Jack, catch that fellow!"
There was a wild scramble, but every time Jack just missed the
dragon-fly. Finally Betty lent him her broad hat, and at last Jack
caught the insect.
"Gee! aren't its eyes big?"
"And beautiful, too," said the guide. "They are made up of thousands of
facets (a facet is just a small, plain surface) as many as thirty
thousand facets in one eye. Some look up, some look down, some look out,
some look in; so that there is nothing that escapes the sight of this
hawk of the air. Look at the wings on this fellow, and look at the
picture I drew for you of the nymph. Well, this fellow's wings begin in
the nymph as tiny sacs, or pads, made by the pushing out of the wall of
the body. Running all through between the two layers of the wing are
thickened lines of chitin, which divide and subdivide, forming this fine
network. In the new wing, protected by these thickenings, are air-tubes,
which divide and branch into all parts of the wing. But as the wing
reaches its full growth most of the air-tubes die." The guide paused.
"We are talking too much and fishing too little. Time to go on. Put out
the fire, boys. Be sure that it's out. Run water all around it. Now
we're off!" And up, up, up the brook they went.