Subterranean Termites are smaller than Drywood termites, approximately one-fourth inch long. They create colonies in the soil and require moisture to survive. Unlike Drywood Termites, they do require a direct connection to soil. They build tubes up the side of concrete foundations or straight out of the ground, making highway tunnels for traveling to their food source and back. They eat all types of wood and occasionally other cellulose material like cardboard or books. The most common evidence of Subterranean Termites is the presence of mud tunnels along the foundation of the house inside or out.