Therevidae, or stiletto flies, are a fairly common family of predominantly xerophilic brachycerous flies. They are found virtually worldwide and are comprised of over 700 species in about 50 genera. Adults feed from a variety of fluid sources including water, plant fluids, and insect secretions and excretions. Larvae are free living in the soil and are predaceous on fossorial organisms including earthworms, and the larvae of other insects such as beetles.
The fossil record is sparse (11 species in 6 genera), no doubt due to their normally being found in xerophilic habitats, which are uncommon sources for fossil insect deposits, except possibly those deposits originating in the more dryer Triassic. One fossil, originally described as a therevid (Psilocephala scudderi Cockerell) has been removed to the genus Desmatomyia Williston in the Bombyliidae after reexamination of the type (Evenhuis, 1990a).
Müller (1977) has shown that the Eocene trace fossil Helicorhaphe Ksiazkiewicz is probably the same as Thereva Latreille. It is treated in this catalog as questionably included in Therevidae pending further study.

Ref.: Hennig (1967c, review of amber taxa).



GLAESORTHACTIA Hennig, 1967c: 3. Type species: Thereva magnicornis Meunier, 1908, by original designation.

magnicornis Meunier, 1908h: 260 (Thereva). PA: Baltic Region (Eocene/Oligocene) [A].


Genus NEBRITUS Coquillett

*NEBRITUS Coquillett, 1894: 187. Type species: Nebritus hubbardii Coquillett, 1898, by original designation.

willistoni Melander, 1949: 30. NE: USA (Oligocene) [C].


Genus PSILOCEPHALA Zetterstedt

*PSILOCEPHALA Zetterstedt, 1838: 525. Type species: Bibio imberbis Fallén, 1814, by subsequent designation of Coquillett (1910: 597).
*PARACLIA Enderlein, 1936: 88. Type species: Bibio imberbis Fallén, 1814, by monotypy.

agilis Meunier, 1908h: 260. PA: Baltic Region (Eocene/Oligocene) [A].
electrella Cockerell, 1920b: 170. OR: Myanmar (Miocene) [A].
pusilla Hennig, 1967c: 10. PA: Baltic Region (Eocene/Oligocene) [A].
tarsalis Statz, 1940: 130 (Paraclia). PA: Germany (Oligocene) [C].


Genus RUEPPELLIA Wiedemann

*RUEPPELLIA Wiedemann, 1830: 625, 663, 675. Type species: Rueppellia semiflava Wiedemann, 1830, by monotypy.
RUPPELLIA. Incorrect original spelling of Rueppellia (Wiedemann, 1830: 625). [By action of first reviser in Bezzi (1903: 213).]

vagabunda Cockerell, 1927a: 163. NE: USA (Oligocene) [C].


Genus THEREVA Latreille

*THEREVA Latreille, 1797: 167. Type species: Musca plebeja Linnaeus, 1758, by subsequent monotypy in Latreille (1802: 441).

bosniaskii Handlirsch, 1907c: 1010. PA: Italy (Miocene) [C].
marcelini Théobald, 1937a: 146. PA: France (Oligocene) [C].
pinguis Loew, 1850b: 40. PA: Baltic Region (Eocene/Oligocene) [A].


Questionably Included in THEREVIDAE

Genus HELICORHAPHE Ksiazkiewicz

HELICORHAPHE Ksiazkiewicz, 1970: 286. Type species: Helicorhaphe tortilis Ksiazkiewicz, 1970, by original designation.

tortilis Ksiazkiewicz, 1970: 286. PA: Poland (Eocene) [T].