More than 40 species live in the United States. A typical colony lives underground in a damp, chamberlike nest. The colony is organized into a caste system with four different adult forms: royalty, nobility, soldiers, and workers. The royalty consists of the kings and queens, which carry on the work of reproduction. They have well-developed wings and eyes. The kings are usually smaller than the queens, which may reach a length of 4.3 inches (11 centimeters) in some species.