Plural: pupae. The name for the third main stage in the life of an insect that undergoes complete metamorphosis, i.e., develops from the egg through larval and the pupal stages to the adult (holometabolous). All Diptera undergo complete metamorphosis and have a pupal stage. Pupae of Diptera are of two main types; obtect pupae have visible head appendages, wings and legs which lie in sheaths attached to the surface of the body (all Diptera except Cyclorrhapha). Exarate pupae (Cyclorrhapha only) have free appendages. These free appedages are not visible as the pupa lies within the last larval instar skin which is hardened (puparium). Such Diptera pupae are called coarctate.
Recommended literature: Smith, K.V.G., 1989. An introduction to the immature stages of British flies. Diptera larvae, with notes on eggs, puparia and pupae. - Handbooks for the Identification of British Insects 10(14): 1-280. As an excellent reference with keys to suborders, families, subfamilies and genera. For Cyclorrhapha the key applies equally since they have puparia (although the parts may be harder to see).
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