As the word "subterranean" means, these termites sometimes live underground. They eat wood and other plant matter in the ground or on top of the soil. They sometimes build tubes out of sand, mud, and other materials to reach wood that is at the surface. There are several species of subterranean termites, and although they are smaller than some other termites, they are the most destructive species in North America but they eat cellulose at a very slow rate.  They also do not go after the important wood on a home i.e. 2x4s and things like that.  They mostly like to go after the backing of drywall, basebaords, and things like that. They have been know to be more of a "cosmetic" damager than a structural damager.  These termites are mostly found in the east and have migrated to the west in the past years. They are only 1/4'' in length. These are by far the easiest termite to exterminate.