The Collaborative International Dictionary of English v.0.48:

Chinch \Chinch\, n. [Cf. Sp. chinche, fr. L. cimex.]
   1. (Zool.) The bedbug (Cimex lectularius).
      [1913 Webster]

   2. (Zool.) A bug (Blissus leucopterus), which, in the
      United States, is very destructive to grass, wheat, and
      other grains; -- also called chiniz, chinch bug,
      chink bug. It resembles the bedbug in its disgusting
      odor.
      [1913 Webster]

WordNet (r) 3.0 (2006):

chinch
    n 1: bug of temperate regions that infests especially beds and
         feeds on human blood [syn: bedbug, bed bug, chinch,
         Cimex lectularius]