Why is paurometabola metamorphosis called gradual?

Paurometabola metamorphosis is called gradual because it involves a continuous transformation without distinct larval stages, leading to the adult form. In this process, the insect undergoes several nymphal stages that resemble the adult in appearance, gradually developing the characteristics of the mature insect over time. This contrasts with complete metamorphosis, where there are clear differences between larval and adult forms. The gradual nature allows for a more seamless transition as the insect matures.