Hairy-Legged Horsefly
Hybomitra bimaculata
This record describes Hybomitra bimaculata (species). Recorded family: Tabanidae. Recorded order: Diptera.
Identification and Appearance
A medium-large, highly variable horsefly with a body length of 13 to 16.5 mm. Both males and females possess long hair fringes on the anterior and posterior surfaces of the mid tibiae with males also having a posteroventral fringe along the length of the hind tibiae with hairs twice as long as the width of the tibia. This latter feature is useful in separating the species from H. lurida, a scarce bogland horsefly. The abdomen varies from all black individuals to those with extensive orange markings along the flanks of the first three tergites. Females have three dark stripes across the eyes but can be separated from the rarer H. micans by the tibiae which are at least partially pale (all black in H. mican) and a paler abdomen. Found in various habitats, including wetlands and open wet woodlands. The predatory larvae develop in wet soil, wood detritus and even waterbird nests. Widespread in the southern half of Britain but seems to be less common further north.
Wikipedia reference for Hybomitra bimaculata: https://en.wikipedia.org/wiki/Hybomitra_bimaculata.
Classification
Habitat and Range
Habitat
Found in various habitats, including wetlands and open wet woodlands.
Seasonal Activity
Summer.
Diet and Behavior
Life History
The predatory larvae develop in wet soil, wood detritus and even waterbird nests.
Additional species information
Recorded status
Widespread in the southern half of Britain but seems to be less common further north.
About Flies: the wider group
Order-level background for Diptera, the group containing Hybomitra bimaculata. Species-specific details appear above.
Group overview
Diptera includes over 150,000 described species of flies, mosquitoes, and midges. Mosquitoes are the deadliest animal on Earth (CDC). Malaria alone causes ~249 million cases and over 608,000 deaths annually, mostly children under 5 (WHO). Vector-borne diseases account for over 17% of all infectious diseases, causing 700,000+ deaths per year.
Ecological role of the group
Despite their disease impact, flies are critical decomposers and pollinators. Hoverflies alone pollinate hundreds of crop and wildflower species. Flies are also the primary food source for many birds, bats, and fish. Forensic entomology relies heavily on fly species for crime scene analysis.
Economic and practical significance of the group
In the U.S., vector-borne disease cases tripled between 2004-2016, with over 640,000 cases reported in that period (CDC). Tickborne diseases doubled from 22,000 to 48,000 annual reports. Globally, mosquito-borne diseases cost billions in healthcare and lost productivity.
Recorded sources for this group: WHO, CDC, PNAS. Imported estimates may describe particular regions or reporting periods.
Frequently Asked Questions About Hairy-Legged Horsefly
What is Hairy-Legged Horsefly?
Hairy-Legged Horsefly (Hybomitra bimaculata) is a species in the family Tabanidae, within the order Diptera.
Where is Hairy-Legged Horsefly found?
Habitat: Found in various habitats, including wetlands and open wet woodlands.
When is Hairy-Legged Horsefly active?
Hairy-Legged Horsefly: seasonal activity - Summer..
What is the life cycle of a Hairy-Legged Horsefly?
The predatory larvae develop in wet soil, wood detritus and even waterbird nests.