In insects, hemimetabolism is the type of development without a separate larval stage. The young of hemimetabolous insects are hatched, (or sometimes born), in a form much like their adult imago form, only smaller and often without functioning wings. Through successive molts, the insect becomes larger and gains adult features, but there is not a clear dividing line between a young and an adult insect.
Hemimetabolism was the original form of insect development. There are many common insect orders that are still hemimetabolist: grasshoppers, bugs and aphids, dragonflies and cockroaches, among others, are all hemimetabolist.
While hemimetabolism might seem like an ideal development strategy, as the insects have a more linear form of development, and hemimetabolist insects are indeed common across many different niches and biomes, they are less successful than the holometabolist insects.