Diagnosis. Medium-sized to very large (6.0-27.0 mm) flies with large eyes. Antennae with six or more segments, usually only basal three segments well developed. Each tarsus with enlarged empodium, therefore apparently three pulvilli present. Scutellum without spines or bristles. Wing venation extended, vein R4+5 split near top of wing. Eyes in living flies brilliantly reddish or metallic green, sometimes yellowish, often with spots or bands; in males holoptic, in females narrowly separated. Upper facets of eye in males often significantly enlarged. Eggs elongate oval or spindle-shaped. Originally milk-white to pale yellowish, becoming soon after oviposition darker, finally very dark grey to almost black; chorion often with surface pattern. Larvae cylindrical or spindle-shaped, tapering at both ends. Last abdominal segment with a terminal vertical fissure and Graber's organ (probably used for sensory perception). Body usually longitudinally striated. Head capsule not strongly sclerotized, and retractile. Pupa obtect, with distinct visible head, thorax and abdomen, with characteristic anal aster and species-specific spines in combs on abdominal segments. Head often has distinct antennal ridge, or paired tubercles between antennal sheaths.
Biology. Females are notorious for bloodsucking on mammals, including man. Feeding on blood is used to develop the eggs but apparently not necessary for the first batch. Females lay eggs usually on leaves of herbs and trees and dry twigs close to or just above water. The eggs are laid in masses of up to 1000 eggs consisting of one (Chrysops) to four layers. Some species can be found on flowers. Males of several species hover territorially (like Syrphidae), of other species males seem quite inactive. Larvae from one egg-mass hatch almost at the same time, one to three weeks after oviposition, and fall onto damp soil or directly onto water. The larvae grow through 6-11 instars and will pupate under dryer conditions in late spring. After one to four weeks the adult emerges usually early in the morning.
General references. Chvála (1988a [catalogue]), Chvála & Ježek (1997 [immature stages]), Chvála et al. (1972 [keys]), Pechuman & Teskey (1981 [general]), Smith (1989 [immature stages]), Zeegers & Van Haaren (2000 [keys to adults & larvae])
References to the local fauna. .Van Aartsen (1992c, 1997), Kabos (1960), Leclercq (1967), Mol (1984), Piet (1946a), Theowald (1953), Timmer (1974, 1979, 1980), Zeegers (2002), Zeegers & Van Haaren (2000).
Remarks. The number of species in Belgium taken from Zeegers & Van Haaren (2000).
Original data by Zeegers & Van Haren, corrections and updates (publication years marked in red) by Beuk.
How to quote this page: Zeegers, Th., T. van Haaren, & P.L.Th. Beuk, 2022. Family Tabanidae. In: Beuk, P.L.Th. (Ed.): Checklist of the Diptera of the Netherlands, https://diptera-info.nl/news.php?fam=Tabanidae (date accessed: 09/06/2026).
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