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.