pterostigmata

from The Collaborative International Dictionary of English v.0.48

Pterostigma \Pter`o*stig"ma\, n.; pl. {Pterostigmata}. [NL., fr.
   Gr. ? wing + ?, ?, a mark.] (Zool.)
   A thickened opaque spot on the wings of certain insects.
   [1913 Webster]