1Any of various European flies of the genus Heleomyza (or Suillia) (family Heleomyzidae), which have larvae that feed on truffles and which can be used as an indicator of the presence of truffles.
2= truffle beetle (now rare).
Origin
Mid 19th century.
Definition of truffle fly in US English:
truffle fly
noun
1Any of various European flies of the genus Heleomyza (or Suillia) (family Heleomyzidae), which have larvae that feed on truffles and which can be used as an indicator of the presence of truffles.