subimago

sub- +‎ imago, after German Subimago.

subimago (plural subimagos or subimagoes or subimagines)

1. (zoology) A stage in the development of certain insects, intermediate between pupa and imago, during which the insect can fly but must shed a skin before becoming mature.
   • 1853, Francis Walker, Catalogue of the Specimens of Neuropterous Insects in the Collection of the British Museum‎, page 538:

     Subimago, Fem.—Dull piceous: antennæ black: abdomen more than twice the length of the thorax: setæ brownish testaceous, mutilated: legs dull testaceous; fore-legs brown: wings gray; veins black, not strongly marked.

   • 1996, Richard W. Merritt, An Introduction to the Aquatic Insects of North America‎, page 126:

     The subimago (a winged, but usually sexually immature stage) in the life cycle of mayflies is unique among living insect orders. The Ephemeroptera have two winged-instars, the subimago and the adult (or imago).

   • 2009, James H. Thorp, Ecology and Classification of North American Freshwater Invertebrates‎:

     Subimagos emerge at the surface, fly to a support, molt immediately to the adult stage, live only a few hours, swarm, and mate shortly after ecdysis.

   • 2011, Rüdiger Wagner, Central European Stream Ecosystems: The Long Term Study of the Breitenbach‎:

     Subimagines flutter away immediately and rest at protected sites near the stream for up to 2-3 days, until the molt to the very short-lived adult occurs.

• pseudimago
• dun (of mayflies)

• bigamous