Source : Webster's Revised Unabridged Dictionary (1913)

Pupa \Pu"pa\, n.; pl. L. {Pup?}, E. {Pupas}. [L. pupa girl.
   doll, puppet, fem. of pupus. Cf. {Puppet}.]
   1. (Zo["o]l.) Any insect in that stage of its metamorphosis
      which usually immediately precedes the adult, or imago,
      stage.

   Note: Among insects belonging to the higher orders, as the
         Hymenoptera, Diptera, Lepidoptera, the pupa is inactive
         and takes no food; in the lower orders it is active and
         takes food, and differs little from the imago except in
         the rudimentary state of the sexual organs, and of the
         wings in those that have wings when adult. The term
         pupa is sometimes applied to other invertebrates in
         analogous stages of development.

   2. (Zo["o]l.) A genus of air-breathing land snails having an
      elongated spiral shell.

   {Coarctate}, or {Obtected}, {pupa}, a pupa which is incased
      in the dried-up skin of the larva, as in many Diptera.

   {Masked pupa}, a pupa whose limbs are bound down and partly
      concealed by a chitinous covering, as in Lepidoptera.

Coarct \Co*arct"\, Coarctate \Co*arc"tate\, v. t. [See
   {Coarctate}, a.]
   1. To press together; to crowd; to straiten; to confine
      closely. [Obs.] --Bacon.

   2. To restrain; to confine. [Obs.] --Ayliffe.

Coarctate \Co*arc"tate\, a. [L. coarctatus, p. p. of coarctare
   to press together; co- + arctare to press together, from
   arctus, p. p. See {Arctation}.] (Zo["o]l.)
   Pressed together; closely connected; -- applied to insects
   having the abdomen separated from the thorax only by a
   constriction.

   {Coarctate pupa} (Zo["o]l.), a pupa closely covered by the
      old larval skin, as in most Diptera.

Source : WordNet®

coarctate
     adj : (of an insect pupa) enclosed in a rigid case