Chilopoda is the order that includes centipedes. They are called this because it appears that they have one hundred legs. They are long and almost worm-like with long spindly legs coming out of their body. Centipedes go through a gradual metamorphosis, where the immature look the same as adults, but smaller. They have an interesting way of combining egg and sperm as well.
The male centipedes deposit a package of sperm for the female to find and take up to combine with her eggs. Some males will spin a web and do a mating dance for the female, while others will just leave the package alone and hope the female finds it.
Females have different locations that they leave their eggs to hatch. Some lay them in a small hole in soil, leaving them behind to fend for themselves. Others will lay more eggs into a nest and actually tend to this nest. Some of these female centipedes will stay with their young even after they have hatched. The eggs are usually covered in a sticky substance to keep them together in clumps of between 10 and 60 eggs.
In order to be classified as a full adult, the centipede must undergo several moults and stages. After hatching from an egg, it will become a larva. The first larval stages are usually quite immobile. After moulting the exoskeleton, the legs will develop in different amounts depending on which order the centipedes belong to. Most centipedes take about a year to reach full maturity, both primitive and epimorphic. Sometimes the centipede may take longer than a year to reach full maturity.
Some orders of centipedes exhibit a primitive condition of development called anamorphy. In this condition, each moult adds more legs to the body of the centipede. These orders of centipedes all end up with 15 segments that can have legs growing from them. The anamorphic centipedes may start out hatching with as little as four pairs of legs and gain a few pairs each time they moult until they reach mature adulthood. These moults all happen during the larval stage of a centipede's life cycle.
Orders that do not exhibit the primitive condition of development undergo what is called epimorphy. Here, they will hatch from their eggs with a full set of 15 pairs of legs. These centipedes usually end up being the longest of all centipede orders. They can have as many as 191 pairs of legs in some cases.