American Horse Fly vs Thick-headed Fly

Side-by-side species comparison

Attribute American Horse Fly Thick-headed Fly
Scientific Name Tabanus americanus Physocephala rufipes
Order Diptera Diptera
Family Tabanidae Conopidae
Size 20-28 mm 8-14 mm
Habitat Ponds & Lakes Underground
Diet Blood Feeders Parasitoids
Regions Eastern and central United States Europe
Conservation Least Concern Least Concern

American Horse Fly

One of the largest horse flies in North America with a dark brown body and conspicuous green or purple iridescent eyes. Females deliver a painful slashing bite to obtain blood meals.

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Did You Know?

Its knife-like mouthparts slice open skin rather than piercing it, which is why horse fly bites bleed so freely.

Thick-headed Fly

A wasp-mimicking fly that parasitizes bumblebees by injecting eggs into them mid-flight.

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Did You Know?

Infected bumblebees bury themselves in soil where the fly larva pupates.