Black Horse Fly vs Lesser House Fly

Side-by-side species comparison

Attribute Black Horse Fly Lesser House Fly
Scientific Name Tabanus atratus Fannia canicularis
Order Diptera Diptera
Family Tabanidae Fanniidae
Size 20-28 mm 5-7 mm
Habitat Farmland Indoors
Diet Blood Feeders Scavengers
Regions Eastern United States from the Great Plains to the Atlantic coast Worldwide
Conservation Least Concern Least Concern

Black Horse Fly

A very large entirely black horse fly and one of the biggest flies in North America. Females are persistent blood-feeders that can harass livestock and humans during summer months.

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Did You Know?

Its larvae are aquatic predators that live in muddy pond bottoms and can take up to two years to complete development.

Lesser House Fly

A small greyish fly often seen flying in circles beneath ceiling lights indoors. It breeds in decaying organic matter and is a secondary forensic indicator.

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Did You Know?

Males are well known for hovering in a fixed triangular flight pattern beneath indoor light fixtures.