Source : Webster's Revised Unabridged Dictionary (1913)

Sphex \Sphex\, n.[NL., fr. Gr. ???, ???, a wasp.] (Zo["o]l.)
   Any one of numerous species of sand wasps of the genus
   {Sphex} and allied genera. These wasps have the abdomen
   attached to the thorax by a slender pedicel. See Illust. of
   {Sand wasp}, under {Sand}.

   {Sphex fly} (Zo["o]l.), any one of numerous species of small
      dipterous flies of the genus {Conops} and allied genera.
      The form of the body is similar to that of a sphex.