Which is NOT a stage in the process of insect metamorphosis?

The correct answer identifies that "Adult-immature" is not a recognized stage in the process of insect metamorphosis. Insect metamorphosis typically includes four primary stages: egg, larva, pupa, and adult. Each of these stages represents a distinct phase in the life cycle of an insect, where significant changes in form and function occur.

The egg stage is where the life cycle begins, followed by the larval stage, during which the insect grows and feeds. The pupal stage is a transformative phase where the larva undergoes significant physiological changes to prepare for the adult stage. Finally, the adult stage represents the fully developed insect, capable of reproduction.

An "adult-immature" stage does not exist as a separate recognized stage in this developmental process. Instead, the adult stage is the final form, contrasting sharply with the immature forms classified under the egg, larval, and pupal stages. Understanding these stages is crucial for the management and control of pest insects, as each stage may require different control measures.