Therevidae Burmeister, 1837

Kevin C. Holston

Department of Entomology, Swedish Museum of Natural History, Frescativägen 40, Box 50007, S-104 05 Stockholm, Sweden; kevin.holston@nrm.se

Small to medium-sized (2.5-18.0 mm) lower Brachycera with short, usually stiletto-like antennal flagellum and elongate or tapered abdomen. Margin of eyes in males meeting at mid-line of upper frons or separated by less than width of ocellar tubercle, widely separated in females with darker tomentum or bare medial areas (often appearing as a single spot or pair of shining spots); proboscis arising from subcranial cavity, labella fleshy; antennal scape and pedicel setose, first flagellomere with or without setae, antennal stylus short and composed of one to three small apical or subapical flagellomeres. Thoracic and scutellar bristles present. Wing membrane clear to opaque, often darker adjacent to cross-veins and distal wing veins, occasionally maculated; discal cell elongate with M1, M2, and M3 arising from its apex. Legs slender, bristles present on femora and tibiae; tibial spurs absent; empodium setiform or absent. Abdomen with eight pregenital segments, separated by light-coloured lateroapical tomentum or cuticle and/or yellowish-white intersegmental membrane; abdomen in males of some species uniformly greyish-white due to dense tomentum and/or adpressed setae. The larvae are elongate predators found in dry or friable substrates including sand dunes and leaf litter; and the known prey includes larvae and pupae of Coleoptera, Lepidoptera and Diptera. Adults are not predaceous but have been observed drinking water or plant and animal secretions (Holston & Niehuis 2002, Spitzer & Barták 2000). Malaise traps have been effective in collecting species in riparian and steppe environments; they can also be hand-collected from the ground in sunny, open habitats or from herbaceous or woody vegetation. They are relatively rare and inconspicuous flies, and several Czech species (Cliorismia ardea, Thereva apicalis, T. microcephala, Pandivirilia melaleuca, P. eximia) are of local and regional conservation interest in northern European, and many European species are associated with xerothermic habitats (Holston & Niehuis 2002, Keil 2003,  Lyneborg & Spitzer 1974, Spitzer & Barták 2000).

Of the 98 European species (Lyneborg 1989), 29 are recorded in this checklist (27 in the Czech Republic, 24 in Bohemia, 26 in Moravia, and 22 in Slovakia) and 20 of them are in the genus Thereva. The previous faunal checklist for the Czech Republic is altered by the addition of Thereva eggeri Lyneborg et Spitzer 1974 (Holston 2006, Spitzer et al. 2005). The genera can be identified with the key to Palaearctic Therevidae (Majer 1997), with keys and diagnoses for species dispersed among several taxonomic revisions (Lyneborg 1968, 1984, 1986a, b). The ecology and distribution of species in the Czech Republic and Slovakia are comprehensively reviewed by Keil (2003, 2005). Thereva unica Harris, 1780, is a senior synonym of Thereva bipunctata Meigen, 1820, following the nomenclature used in the Catalogue of Palaearctic Catalogue (Lyneborg 1989) and the Fauna Europaea (Holston 2004).

References

[1] Holston K. 2004: Fauna Europaea: Therevidae. In Pape T. (ed.): Fauna Europaea: Diptera, Brachycera. Fauna Europaea version 1.1, http://www.faunaeur.org

[2] Holston K.C. 2006: New locality records for Thereva eggeri Lyneborg and Spitzer a notable European stiletto fly (Insecta, Diptera, Therevidae), in the Czech Republic and Greece. Entomofauna carpathica 18: 29-30

[3] Holston K.C. & Niehuis M. 2002: Stiletto flies (Diptera: Therevidae) from a xerothermic locality in the Middle Rhine Valley (Rhineland-Palatinate). Fauna und Flora in Rheinland-Pfalz 9: 1193-1202.

[4] Keil P. 2003 : Habitat and microhabitat preferences of mountain Therevidae (Diptera), and ecological outline of Czech Therevidae. Thesis, University of South Bohemia, Faculty of Biological Sciences, 23 pp.

[5] Keil P. 2005: Microhabitat preferences of stiletto fly larvae (Diptera: Therevidae) in a mountain primeval forest. Studia dipterologica 12: 87-92.

[6] Lyneborg L. 1968: Notes on British Therevidae (Diptera). Proceedings of the Royal Entomological Society, London 37: 170-174.

[7] Lyneborg L. 1984: Ammothereva, a new Palaearctic genus of Therevidae, with a review of the 13 included species (Insecta, Diptera). Steenstrupia 10: 205-222.

[8] Lyneborg L. 1986a: The Palaearctic species of Pandivirilia Irwin & Lyneborg 1981 (Insecta, Diptera, Therevidae). Steenstrupia 12: 85-98.

[9] Lyneborg L. 1986b: The genus Acrosathe Irwin & Lyneborg 1981 in the old world (Insecta, Diptera, Therevidae). Steenstrupia 12: 101-113.

[10] Lyneborg L. 1989: Family Therevidae. In Soós A & Papp L. (eds): Catalogue of Palaearctic Diptera. Vol. 6. Akadémiai Kiadó, Budapest, pp. 11-35.

[11] Lyneborg L. & Spitzer K. 1974: The Czechoslovak species of Thereva Latr. (Therevidae, Diptera), with the description of a new species from Hungary and Austria. Sborník Jihočeského muzea v Ceských Budĕjovicích. Přírodní vědy (MDO) 14: 13-42

[12] Majer J.M. 1997: Family Therevidae. In Papp L. & Darvas B. (eds): Contribution to a Manual of Palaearctic Diptera (with special reference to flies of economic importance), Vol. 2 Nematocera and Lower Brachycera. Science Herald, Budapest, pp. 519- 529.

[13] Spitzer K. & Barták M. 2000: Therevidae. In Barták M. & Vaňhara J. (eds): Diptera in an industrially affected region (North-Western Bohemia, Bílina and Duchcov environs), I. Folia Facultatis Scientiarium Naturalium Universitatis Masarykianae Brunensis, Biologia 104: 159-162.

[14] Spitzer K., Barták M. & Kubík Š. 2005: Therevidae. In Barták M. & Kubík Š. (eds): Diptera of Podyjí National Park and its Environment. Praha, pp. 141-143.