According to The Children's Butterfly Site, there are approximately 12,000 to 15,000 species of butterflies in the world, and scientists believe there are thousands of species that have not yet been found. According to The Butterfly Website, the most common butterfly is the Cabbage White while the rarest butterfly is the Queen Alexandra's Birdwing, which is found only in the rain forest of New Guinea.
Butterflies are in a group of insects call Lepidoptera, according to The Children's Butterfly Site. They have a head, thorax, abdomen, two antennae, six legs and four wings that are almost always covered with colored scales. They also have a coiled proboscis that allows them to drink nectar from flowers.
The Children's Butterfly Site describes a butterfly as having a complete life cycle, which means it goes through the egg, larva, pupa and adult stages. It begins as an egg, a tiny ribbed structure that is attached to a leaf or flower stem. From there, it hatches into a caterpillar, the larva stage, where it eats and grows. Next is the pupa stage, where the caterpillar creates a chrysalis in which it transforms into an adult insect. It emerges from the chrysalis as a butterfly, which is the final mobile and reproductive stage of the insect.