Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
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ametabolous metamorphosis Gradual metamorphosis of a grasshopper Horned Passalus life stages - Odontotaenius disjunctus Hypermetamorphosis of Striped Blister Beetle - Epicauta vittata Holometabolous metamorphosis Black swallowtail, collage of metamorphosis, 3 stages - Papilio polyxenes - male
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
No Taxon (Glossary)
No Taxon (M)
No Taxon metamorphosis
Explanation of Names
From Greek, meta change of, morphe form, plus sis a condition or state (1).
metamorphosis noun - transformation in form of an insect or other arthropod during successive stages of development. Sometimes refers in particular to the change from larva to adult of an insect with complete metamorphosis. Metamorphosis can be classified as:
Note that usage of terminology is not completely consistent. The terminology below is based on Borror et al. (2).

I-Insects undergoing simple metamorphosis typically have a three-stage life cycle:
1-embryo (egg)
2-nymph (resemble small adults)
3-adult (sexually mature, wings typically functional)

Simple metamorphosis may be further divided into three types:
1-ametabolous development (no metamorphosis). The adults and nymphs are wingless, and there is no visible change in form between the stages, other than in size. Ametabolous development occurs in the Apterygota and in other groups that undergo simple metamorphosis where the adults are wingless.

2-hemimetabolous development (incomplete metamorphosis). Immature insects (nymphs, often called naiads) are aquatic and breathe via gills. This pattern of development occurs in:
Ephemeroptera (mayflies)
Odonata (dragonflies and damselflies)
Plecoptera (stoneflies)

3-paurometabolous development (gradual metamorphosis). Nymphs resemble small adults and typically have external wing buds. They live in the same habitat as adults, typically taking the same food. Characteristic of many orders, for example:
Hemiptera (true bugs and allies)
Orthoptera (grasshoppers and allies)

II-Insects undergoing complete metamorphosis have a four-stage life cycle:
1-egg (embryo)
2-larva, typically worm-like with several stages (instars)
3-pupa (resting, transformative stage)
4-imago (adult, sexual stage, typically winged)

An insect that undergoes complete metamorphosis is called holometabolous. The following orders have this type of development:
Neuroptera - Antlions, Lacewings and Allies
Coleoptera - Beetles
Hymenoptera - Ants, Bees, Wasps and Sawflies
Trichoptera - Caddisflies
Lepidoptera - Butterflies and Moths
Mecoptera - Scorpionflies, Hangingflies and Allies
Diptera - Flies
Siphonaptera - Fleas
Strepsiptera - Twisted-winged Insects

IIA-certain insects undergo hypermetamorphosis, with an active first-instar larva (planidium). Examples occur among beetles:
Ripiphoridae - Wedge-shaped Beetles
Meloidae - Blister Beetles

III-Several intermediate types of metamorphosis are known, that do not fit neatly into the classification of simple/complete above. These include:
Order Thysanoptera - Thrips
Family Aleyrodidae - Whiteflies (Order Hemiptera)
Males of superfamily Coccoidea - Scales (Order Hemiptera)
Print References
Gordh, A Dictionary of Entomology, various entries (1)
Borror et al., An Introduction to the Study of Insects (2)
Internet References
Wiktionary: metamorphosis
Wikipedia: Metamorphosis
Australian Museum--Insect Metamorphosis
Works Cited
1.A Dictionary of Entomology
George Gordh, David H. Headrick. 2003. CABI Publishing.
2.Borror and DeLong's Introduction to the Study of Insects
Norman F. Johnson, Charles A. Triplehorn. 2004. Brooks Cole.