Blood fills the whole cavity of the grasshoppers body and bathes all the organs and muscles. The blood is circulated by a long tube that lies just under the exoskeleton of the back. This tube extends almost the entire length of the body. The pumping part of the tube lies in the abdomen, and is called heart. The front part of the tube extends into the head and is called the aorta.
Blood enters the tube through little openings called ostia , along the sides.
The openings have valves that allow blood to enter the tube, but not flow out. As the heart contracts, the blood is forced along the tube and out through the aorta. The blood first bathes the brain, and then flows to other parts of the body. It then re-enters the tube through the ostia. An insect's blood, like ours carries food and waste products to and from the cells of the body.