*coarctate*

a. [ L. coarctatus, p. p. of coarctare to press together; co- + arctare to press together, from arctus, p. p. See Arctation. ] (Zool.) Pressed together; closely connected; -- applied to insects having the abdomen separated from the thorax only by a constriction. [ 1913 Webster ]

Coarctate pupa (Zool.), a pupa closely covered by the old larval skin, as in most Diptera. [ 1913 Webster ]