• Minimal physical change between stages; egg-nymph-adult.
• lack wings
• same feeding environments between stages.

Ex. Arachnids, Thrips, Springtails, lice and silverfish 

• Minimal physical change between stages
• egg-nymph-adult
• adults have wings
• same feeding environments between stages

Ex. Grasshoppers, aphids, booklice, termites, true bugs, earwigs, mantids 

• Extreme physical change between stages
• egg-nymph-adult
• Naiad is aquatic, adult is terrestial
• adult has wings
• diff. feeding environments between stages

Ex. Dragonflies, mayflies and stoneflies 

• Extreme physical change between stages
• egg-larvae-pupae-adult
• most adults have wings
• diff. feeding environments between stages
• hypermetamorphosis

Ex. beetles, butterflies, wasps, fleas, flies, ants and bees 

• Ecdysis- 4-8 instars in most insects
• Ecdysone-molting hormone
• Juvinile hormone controls stage change. low levels-stage to stage. High levels-instar to instar
• Insec Growth Regulator (IGR); synthetic chemical that affects insects. it prevents them from molting.
• Juvinile Hormone (JH); a hormone that prevents growth.

Remains soft and gives flexibility to exoskeleton.

Cells periodically secrete new epi, exo and endocuticle prior to molting. Prior to sclerotization and tanning and subsequent to molting, insect stretches new exoskeleton to larger size.