The Collaborative International Dictionary of English v.0.48:

Scutellum \Scu*tel"lum\, n.; pl. Scutella. [NL., neut. dim. of
   L. scutum a shield.]
   1. (Bot.) A rounded apothecium having an elevated rim formed
      of the proper thallus, the fructification of certain
      lichens.
      [1913 Webster]

   2. (Zool.)
      (a) The third of the four pieces forming the upper part of
          a thoracic segment of an insect. It follows the
          scutum, and is followed by the small postscutellum; a
          scutella. See Thorax.
      (b) One of the transverse scales on the tarsi and toes of
          birds; a scutella.
          [1913 Webster]