This is called camouflage. All insects hatch from eggs. As they grow, they get bigger and begin to look more like their parents. The change the insects go through from egg to adult is called metamorphosis. There are different kinds of metamorphosis.
Some insects change by just growing bigger.
Others grow wings. But there are some insects, such as butterflies, that change so much that the adult looks like nothing like the youth. Dragonflies look for their food during the daytime. It is easier to find with big eyes. Those big eyes also help them watch out for enemies that would catch them.