Termites have been around for over 120 million years. They are social insects and live in colonies which are usually located in the ground or in wood. Most termites feed on cellulose from wood and wood by-products such as paper. They are worldwide in distribution, with about 3,000 described species, and about 50 species are found in the United States. Termites are usually divided into three groups based on the location of their colony: the subterranean, the drywood, and the dampwood termites. The biology and habits of each group are different, so a detailed knowledge of each is necessary for effective control.