Hemolymph flows through this blood vessel but also throughout the insect's body cavity, making the circulatory system open. The heart is divided into a series of chambers, and lining each chamber is a pair of thin, sheetlike muscle bands. The movement of these muscles pumps hemolymph throughout the blood vessel. The other major system we can readily see is the respiratory system. The spiracles, trachea, and tracheoles are the main structures in this system, which function in gas transport and exchange.
Carbon dioxide leaves the body through the spiracles.
An introduction to the study of insects, 6th edition. Harcourt Brace College Publishers.