Insect identifier · Biting flies
How to identify a Stable fly
Stomoxys calcitrans
· Also called dog fly, beach fly, stomoxys, fly that bites ankles, dog fly identification, house fly bite
If something that looks like a house fly bit your ankles, it was almost certainly a stable fly. True house flies do not bite.
Looks like a house fly, bayonet beak, ankles, patio or beach wrack. True house flies do not bite. Fans help; they are weak fliers. Rotting hay and seaweed piles are the larval story. A line of pinprick welts on the lower legs after a cookout is this page.
What does a stable fly look like?
House-fly size, gray, checkerboard abdomen, bayonet proboscis sticking forward. Prefers ankles. Breeds in rotting vegetation, hay, and seaweed piles (“dog flies” on Florida beaches).
Stable fly (Stomoxys calcitrans) is House-fly size, 5–7 mm. Colors people notice: gray, black. Field marks: Looks like a house fly but has a bayonet proboscis sticking forward; Checkerboard abdomen; Prefers ankles and lower legs; Breeds in rotting vegetation, hay, and seaweed piles. It is found outdoor. If those marks are missing, open House fly, Horn fly before you force this name. Search phrases that belong on this page include what a stable fly looks like and stable fly identification.
Identification marks
- Looks like a house fly but has a bayonet proboscis sticking forward
- Checkerboard abdomen
- Prefers ankles and lower legs
- Breeds in rotting vegetation, hay, and seaweed piles
Size: House-fly size, 5–7 mm
Colors: gray, black
Where: outdoor
What a typical stable fly bite looks like
Sharp pinprick on the ankle, often through socks. Small itchy red spots in a line or cluster on lower legs.
People searching “stable fly bite identification” want the pattern, not a single anonymous bump. Sharp pinprick on the ankle, often through socks. Small itchy red spots in a line or cluster on lower legs. Immediate steps on this page: Soothe ankles; avoid scratching; Move upwind from wrack lines or manure; Wash bites. This species does bite or sting people. Fever, spreading redness, trouble breathing, or a child with many stings is professional care.
If you were bitten
- Soothe ankles; avoid scratching
- Move upwind from wrack lines or manure
- Wash bites
Stable fly vs House fly
Looks like a house fly, bites like a needle, prefers ankles. House flies sponge, they do not bite. Horn flies stay on cattle. Mosquitoes are smaller and hum.
- House fly identification (Musca domestica)
- Horn fly identification (Haematobia irritans)
- Horse fly identification (Tabanus spp.)
- Cluster fly identification (Pollenia spp.)
Range and season
Warm months; year-round in the far South. Fans on patios help — they are weak fliers.
Barns, patios near livestock, and Florida beaches with wrack (“dog flies”).
Worldwide, including all of North America. “Dog flies” on Florida beaches are this species.
Warm months; year-round in the far South
Common questions
Why am I bitten on the ankles by “house flies”?
Those are likely stable flies. True house flies do not bite.
Are they the same as no-see-ums?
No. Stable flies are visible house-fly size. No-see-ums are tiny midges.
Do they spread disease to people?
They are mainly a painful nuisance for people; they matter more as livestock pests.
What looks like a house fly but bites?
A stable fly. True house flies do not bite. Stable flies have a stiff proboscis pointing forward.
Do house flies bite?
No. A “house fly” that bites ankles is a stable fly.
Why do flies bite my ankles on the patio?
Stable flies. Fans help; they are relatively weak fliers.