The Formosan subterranean termite (FST) worker buccal cavity is enclosed by the mandibles and the maxillae (lateral), the labrum (top), and the labium (bottom). Each mouthpart synchronized to perform four-step tunneling behaviors including excavating sand, loading sand into buccal cavities, moving sand, and depositing sand. Termite tunneling behaviors were observed in the two-dimensional arenas with multiple color sand. Workers excavated, loaded and deposited sand particles by maxillae. The mandibles opened and held the sand particles until workers arrived at the deposition site. The labrum covered the cleft between two mandibles and prevented sand particles from slipping out. The labium spread downward for loading and propping up sand particles. The average number of sand particles (0.300 to 0.355 mm) moved by one worker per trip was 3.5±0.15 (± SE). The average head width was 1.18±0.01 mm (± SE). Not all particles in a trip were deposited at the same site along the tunnel walls or empty space. At deposition sites, workers twisted heads and adjusted sand particles with maxillae to fit the wall edge. Previous studies speculated that subterranean termites may press sand particles to either side by pushing heads and exterior surfaces of mandibles during excavation. In order to verify if sand particles were pressed, the locations of sand particles surrounding tunnel tips were examined by superimposing two photographs of tunnel tips taken before and after tunnels were excavated. The comparison showed sand particles surrounding tunnel tips remained stationary, so FST did not press sand to either side.