Grasshoppers and other insects have open circulatory systems, which means that their blood is not contained in closed arteries or veins.

Insects have open circulatory systems. They don’t have any blood vessels. Their hemolymph just sloshes around in their bodies. They have a heart, but it’s not like yours.

How do insects control the effects of gravity when they climb a tree or hang upside-down waiting for prey? They don't have closed circulatory systems that restrict fluid flow to certain parts ...