• Webster's Revised Unabridged Dictionary
    • n. pl Ametabola (Zoöl) A group of insects which do not undergo any metamorphosis.
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Century Dictionary and Cyclopedia
    • ametabola In zoology, insects which do not undergo metamorphosis. In Macleay's system of classification, a term borrowed from W. E. Leach to designate a subclass of Insecta by which the myriapodous, thysanurous, and anoplurous “insects” should be collectively contrasted with the true insects, which undergo metamorphosis. Myriapods being excluded from the class Insecta, and lice being located with insects that are not thoroughly ametabolous, Ametabola is by some authors restricted to the collembolous and thysanurous insects. The term is correlated with Hemimetabola and with Metabola.
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Webster's Revised Unabridged Dictionary


In literature:

Ametabola -ous: insects without obvious metamorphoses, in which the larvae usually resemble the adult and the pupae are active.
"Explanation of Terms Used in Entomology" by John. B. Smith