Gateway to the Classics: Handbook of Nature Study: Invertebrates by Anna Botsford Comstock
 
Handbook of Nature Study: Invertebrates by  Anna Botsford Comstock

Daddy-Longlegs, or Grandfather Greybeard

Teacher's Story

dropcap image WONDER if there ever was a country child who has not grasped firmly the leg of one of these little sprawling creatures and demanded: "Grandfather Greybeard, tell me where the cows are or I'll kill you," and Grandfather Greybeard, striving to get away, puts out one of his long legs this way, and another that way, and points in so many directions that he usually saves his life, since the cows must be somewhere. It would be more interesting to the children and less embarrassing to the "daddy" if they were taught to look more closely at those slender, hairlike legs.

"Daddy's" long legs are seven jointed. The first segment is seemingly soldered fast to the lower side of his body, and is called the coxa. The next segment is a mere knob, usually black and ornamental, and is called the trochanter. Then comes the femur, a rather long segment directed upward; next is a short swollen segment—the "knee joint" or patella; next the tibia, which is also rather long. Then comes the metatarsus and tarsus, which seemingly make one long downward-directed segment, outcurving at the tips, on which the "daddy" tip-toes along.


[Illustration]

One of "daddy's" long legs with segments named.

I have seen a "daddy" walk into a drop of water and his foot was never wetted, so light was his touch on the water surface film. The second pair of legs is the longest; the fourth pair next, and the first pair usually the shortest. The legs of the second pair are ordinarily used in exploring the surroundings. Notice that, when the "daddy" is running, these two legs are spread wide apart and keep in rapid motion; their tips, far more sensitive than any nerves of our own, tell him the nature of his surroundings, by a touch so light that we cannot feel it on the hand. We have more respect for one of these hairlike legs, when we know it is capable of transmitting intelligence from its tip.

The "daddy" is a good traveler and moves with remarkable rapidity. And why not? If our legs were as long in comparison as his, they would be about forty feet in length. When the "daddy" is running, the body is always held a little distance above the ground; but when the second pair of legs suggests to him that there may be something good to eat in the neighborhood, he commences a peculiar teetering motion of the body, apparently touching it to the ground at every step; as the body is carried tilted with the head down, this movement enables the creature to explore the surface below him with his palpi, which he ordinarily carries bent beneath his face, with the ends curled up under his "chin." The palpi have four segments that are easily seen, and although they are ordinarily carried bent up beneath the head, they can be extended out quite a distance if "daddy" wishes to test a substance. The end segment of the palpus is tipped with a single claw

Beneath the palpi is a pair of jaws; these, in some species, extend beyond the palpi. I have seen a daddy-longlegs hold food to his jaws with his palpi and he seemed also to use them for stuffing it into his mouth.

The body of the daddy-longlegs is a little oblong object, looking more like a big grain of wheat than anything else, because in these creatures the head, thorax and abdomen are all grown together compactly. On top of the body, between the feeler-legs, is a little black dot, and to the naked eye it would seem that if this were an organ of sight the creature must be a Cyclops with only one eye. But under the lens this is seen to be a raised knob and there is on each side of it, a little shining black eye. We hardly see the use of two eyes set so closely together, but probably the "daddy" does.


[Illustration]

Grandfather-greybeard.

Comstock's Manual.

The most entertaining thing which a "daddy" in captivity is likely to do, is to clean his legs; he is very particular about his legs, and he will grasp one close to the basal joint in his jaws and slowly pull it through, meanwhile holding the leg up to the jaws with the palpi, while he industriously nibbles it clean for the whole length to the very toe. Owing to the likelihood of his losing one of his legs, he has the power of growing a new one; so we often see a "daddy" with one or more legs only half grown.

There are many species of daddy-longlegs in the United States, and some of them do not have the characteristic long legs. In the North, all except one species die at the approach of winter; but not until after the female, which, by the way, ought to be called "granny-longlegs," has laid her eggs in the ground, or under some protecting stone, or in some safe crevice of wood or bark. In the spring the eggs hatch into tiny little creatures which look just like the old daddy-longlegs, except for their size. They get their growth like insects, by shedding their skins as fast as they outgrow them. It is interesting to study one of these cast skins with a lens. There it stands with a slit down its back, and with the skin of each leg absolutely perfect to the tiny claw! Again we marvel at these legs that seem so threadlike, and which have an outer covering that can be shed. Some say that the daddy-longlegs live on small insects which they straddle over and pounce down upon, and some say they feed upon decaying matter and vegetable juices. This would be an interesting line of investigation for pupils, since they might be able to give many new facts about the food of these creatures. The "daddies" are night prowlers, and like to hide in crevices by day, waiting for the dark to hunt for their food. They have several common names. Besides the two given they are called "harvestmen" and the French call them "haymakers." Both of these names were very probably given, because the creatures appear in greater numbers at the time of haying and harvesting.

Lesson CIX

The Daddy-Longlegs

Leading thought—These long-legged creatures have one pair of legs too many to allow them to be classed with the insects. They are more nearly related to the spiders, who also have eight legs. They are pretty creatures when examined closely, and they do many interesting things.


Method—Put a grandfather greybeard in a breeding cage or under a large tumbler, and let the pupils observe him at leisure. If you place a few drops of sweetened water at one side of the cage, the children will surely have an opportunity to see this amusing creature clean his legs.


Observations—

1. Where did you find the harvestman? What did it do as soon as it was disturbed? How many names do you know for this little creature?

2. A "daddy" with such long legs certainly ought to have them studied. How many segments in each leg? How do the segments look? How do the legs look where they are fastened to the body? Which is the longest pair of legs? The next? The next? The shortest?

3. If you had such long stilts as he has, they would be about forty feet long. Would you lift yourself that high in the air? Does the "daddy" lift his body high or swing it near the ground? What shape is the body? Can you see if there is a distinct head? Can you see a black dot on top of the front end of the body? If you should see this dot through a microscope it would prove to be two bright black eyes. Why should the daddy's eyes be on top?

4. Do you see a pair of organs that look like feelers at the front end of the body? These are called palpi. How does he use his palpi? Give him a little bruised or decaying fruit, and see him eat. Where do you think his mouth is? Where does he keep his palpi when he is not using them for eating?

5. Note what care he takes of his legs. How does he clean them? Which does he clean the oftenest? Do you think the very long second pair of legs is used as much for feeling as for walking? Put some object in front of the "daddy" and see him explore it with his legs. How much of the leg is used as a foot when the "daddy" stands or runs?

6. When running fast, how does the "daddy" carry his body? When exploring how does he carry it? Do you ever find the "daddy" with his body resting on the surface on which he is standing? When resting, are all eight of his legs on the ground? Which are in the air? Is the head end usually tilted up or down?

7. Do you see the daddy-longlegs early in the spring? When do you find him most often? How do you suppose he passes the winter in our climate? Have you ever seen a "daddy" with one leg much shorter than the other? How could you explain this?

8. Try and discover what the daddy-longlegs eats, and where he finds his food.


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