In biology, the imago (Latin for "image") is the last stage an insect attains during its metamorphosis, its process of growth and development; it is also called the imaginal stage, the stage in which the insect attains maturity. It follows the final ecdysis of the immature instars.
In a member of the Ametabola or Hemimetabola, in which metamorphosis is "incomplete", the final ecdysis follows the last immature or nymphal stage. In members of the Holometabola, in which there is a pupal stage, the final ecdysis follows emergence from the pupa, after which the metamorphosis is complete, although there is a prolonged period of maturation in some species.
Members of the order Ephemeroptera (mayflies) do not have a pupal stage, but they briefly pass through an extra winged stage called the subimago. Insects at this stage have functional wings but are not yet sexually mature.
- Carpenter, Geo. H., The Life-Story of Insects. Cambridge University Press 1913. May be downloaded from: https://www.gutenberg.org/ebooks/16410 or https://archive.org/details/thelifestoryofin16410gut
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- Gordh, Gordon; Headrick, David H. A Dictionary of Entomology. Publisher: CABI 2010. ISBN 978-1845935429