Domenic Baffa, age 9, of Erie, Pa., for his question:
DOES A CATERPILLAR HAVE LEGS?
A caterpillar is a wormlike creature that is in the second, or larval, state in the life history of moths and butterflies. The caterpillar has three pairs of five jointed legs. These legs later develop into the legs of the adult insect.
A caterpillar usually has 12 rings or segments, not including the head. The three pairs of legs are attached to the first three segments of the body. But the leg like prolegs on the abdomen are not really legs and they are shed with the last skin.
Occasionally, as in the so called measuring worms, there are two pairs of prolegs on the abdomen and the larva moves by drawing these hind legs up to the front pair.
On the caterpillar's head are six simple eyes on each side. The creature guides itself by a pair of short, jointed feelers. Its strong, biting jaws differ from the sucking mouth parts of the butterfly. The body may be naked or covered with hairs, bristles or spines.
As the caterpillar grows, its skin does not grow with it as does the akin of most animals. Soon the skin becomes too tight and the caterpillar prepares to throw it off. A split appears on the upper part, near the head end, and the caterpillar wriggles out.
The caterpillar then appears in a new soft skin formed under the old one. In a few days this, too, is outgrown, and the process is repeated a number of times.
In the temperate regions, most species remain in the caterpillar stage from two to four weeks. In very cold climates, some species take from two to three years to pass from the egg to the butterfly stage
Some caterpillars have glands that secrete an unpleasant fluid. Others have a sickening taste which saves them from being eaten by birds and other animals.
False eyespots help frighten away attackers of some caterpillars, while long, whiplike appendages on the backs of other larvae are lashed about as a means of defense.
Despite many defense devices, very few caterpillars that are hatched ever reach the adult stage. Larger animals eat them and parasites burrow into their bodies and kill them.
Caterpillars are heavy eaters. They dine on plant leaves.
A butterfly or moth does all its growing during the caterpillar stage. The larvae stores up the tissues that later are transformed into the adult insect. The adult grows no more after it grows wings.
A few larvae, such as the silkworms, are valuable, but most are not. Sometimes, in years when caterpillars are numerous, fields are made bare of vegetation and trees are stripped of their leaves. The cabbage worm, the cotton worm, the army worm and the cutworms are especially troublesome.
A chrysalis is the third or pupal stage in the life cycle of the butterfly. When the caterpillar (butterfly larva) is mature, it shads its skin and dvelops the hard shell covering of the chrysalis.
The chrysalis hangs from a silk pad by a spike, or by this and a loop of silk around the body. It has no cocoon. The body of the butterfly develops under the hard shell of the chrysalis. Finally, the covering breaks open and the butterfly emerges.