In insects, gaseous exchange takes place through a network of tubes collectively known as the tracheal system. The small openings on the sides of an insect’s body are called spiracles and oxygen-rich air enters through the spiracles. These spiracles are connected to the network of tubes. From the spiracles, oxygen enters the tracheae and from here, oxygen diffuses into the cells of the body. The movement of carbon dioxide follows the reverse path and the CO2 from the cells of the body first enters the tracheae and then leaves the body through the spiracles.