Final answer:
Stoneflies have a hemimetabolous life cycle, going through stages of egg, nymph, and adult, with no distinctly different larva or pupa stage.
Step-by-step explanation:
The life stages of a stonefly which has hemimetabolous development are egg, nymph, and adult. Hemimetabolous, also known as incomplete metamorphosis, is a type of development in which the insect hatches from an egg and goes through several nymphal stages. Each nymphal stage looks like a smaller version of the adult but without functional wings. In the final nymphal stage, the insect molts and emerges as a winged adult capable of reproduction. Unlike complete metamorphosis, which includes a larva and often a pupa stage, stoneflies and other insects undergoing incomplete metamorphosis do not have a drastically different larval stage and there is no pupal stage where they would be immobile and reorganize into adult form.