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Identification & Distribution:


Hybomitra ciureai is a medium to large horsefly with a body length of 14.5 mm. The female has extensive orange side markings on the abdomen extending from tergite 1 to tergite 4 (see first picture below). The extent of the orange side markings distinguishes Hybomitra ciureai from Hybomitra solstitialis and some forms of Hybomitra bimaculata, which only have orange side markings on tergites 1-3 or 1-2.


The bases of the antennae (antennal segment 1) are orange - hence the name "yellow-horned levels horsefly" (see second picture above). This character can be used to distinguish Hybomitra ciureai from another much commoner orange Hybomitra, Hybomitra distinguenda, which has the bases of the antennae grey-black.

A more reliable way to separate females of these two Hybomitra species is to examine the colour of the hairs on the lateral thirds of the second tergite. The female Hybomitra ciuraei has distinct areas of black hairs on the orange ground colour, whilst female Hybomitra distinguenda has only orange hairs.

The male of Hybomitra ciureai (not figured here) has the first antennal segment reddish-brown. The upper facets of the eye are bigger than the lower ones and sharply segregated. The middle stripe of the abdomen is more brownish, less strongly defined and sometimes interrupted.

Distribution & Seasonal Occurrence

Hybomitra ciureai is considered rare in Britain and is an RDB3 species (red data book species, vulnerable). It was formerly thought to be restricted to the Essex coast, but is now known to be found on grazing marsh in several south eastern coastal areas from Norfolk round to Hampshire (Drake 1991). Hybomitra ciureai is much commoner over many parts of Europe than in Britain and is found through to Russia, China and Mongolia. The flight period is mid-June to mid-August.


Biology & Ecology:

Resting behaviour & Swarming

Whilst males of Hybomitra distinguenda and Hybomitra muehlfeldi are excellent and persistent hoverers, male Hybomitra ciureai do not hover, but sit on leaves on the look-out. On warmer evenings they can be taken at light.

Blood feeding

In Britain the hosts are likely to be cattle and horses and possibly sheep. No blood meal analysis has been carried out to determine feeding patterns of this species.

Nectar feeding & puddling

Both male and female Hybomitra ciureai probably take nectar from flowers (Kniepert, 1980) as well as blood from mammalian hosts.

Trapping & odour attractants

Some work has been done to test the effectiveness of different odour attractants for Hybomitra ciureai. In Croatia Krčmar et al. (2006) found that canopy traps baited with aged cow urine collected more Hybomitra ciureai females than did unbaited traps, and more than traps baited with aged horse, sheep, or pig urine. There was also evidence that 4-methylphenol and 3 -isopropyl -phenol (two of the active chemicals in cow urine) increased the catch of Hybomitra ciureai (Krčmar, 2007).

Hybomitra ciureai is one of the commoner species of tabanids in eastern Europe. Krčmar & Leclercq (1997) found that Hybomitra ciureai together with Hybomitra muehlfeldi and Hybomitra acuminata made up over 50% of the horse fly fauna on the lower part of the Netretva River in southern Croatia.

We have caught the species in Britain using cow urine/acetone - baited NG2F traps at Rye Harbour, East Sussex (Brightwell & Dransfield, 2014). Traps sited in open grassland near Castle Water and in rough ground near contaminated pools (lagoons) caught four females in a few hours. Single males of this species were last taken at Rye Harbour in the Wood (June 2010) and in Rye Harbour Village (July 2010).


  • Brightwell, R. & Dransfield, R.D. (2014). Survey of Tabanidae (horseflies) in southern England 2014. A preliminary survey of tabanids using odour-baited NG2F traps. 14 pp. Full text

  • Drake (1991). Provisional Atlas of the Larger Brachycera of Britain and Ireland. Institute of Terrestrial Ecology. NERC. Full text

  • Kniepert, F.W. (1980). Blood-feeding and nectar-feeding in adult Tabanidae (Diptera). Oecologia 46, 125-129. Abstract

  • Krčmar, S. & Leclercq, M. (1997). Horse flies (Diptera: Tabanidae) on the lower part of the Neretva river in Southern Croatia. Bulletin and Annales de la Societe Royale Belge d'Entomologie 133(2), 267-274.

  • Krčmar, S. et al. (2006). Response of Tabanidae (Diptera) to different natural attractants. Journal of Vector Ecology 31(2), 262-265. Full text

  • Krčmar, S. (2007). Response of Tabanidae (Diptera) to canopy traps baited with 4-methylphenol, 3-isopropylphenol, and napthalene. Journal of Vector Ecology 31(2), 188-192. Full text