🪰 Flies & mosquitoes

House fly

Musca domestica

Four dark stripes behind the head, and a breeding site you can usually find.

Size
About a quarter of an inch
Colour
Dull grey, with a paler abdomen
Risk
Moderate
When
Peaks in warm months; a few persist indoors through winter
A house fly in profile: a grey bristly fly with large red compound eyes and translucent veined wings.
The four dark lengthwise stripes on the thorax are the separator from other grey flies, and are clearest from directly above. AI-generated illustration · FreePestControlInspection.com

How to identify it

Work down these in order — the first one is usually enough on its own.

  • Four dark lengthwise stripes on the thorax — the identifier
  • Large reddish compound eyes
  • One pair of wings; the hind pair is reduced to small knobs
  • Sponging mouthparts, so it cannot bite

What it gets mistaken for

Most people arrive at a pest name by ruling things out. These are the ones that genuinely look similar, and the detail that separates them.

Where you will find it

  • Kitchens, and around bins inside and out
  • Anywhere organic matter is decomposing — compost, pet waste, a neglected drain
  • Sunny windows, where they collect trying to get out
  • Around pet areas and livestock

Signs it is already there

You will nearly always see the evidence before you see the pest itself.

  • Small dark specks on windows, light fittings and ceilings
  • A cluster of flies at one particular window
  • A sudden indoor population, which means something nearby is breeding them

Moderate. Worth dealing with, but not an emergency.

Why it is harder to deal with than it looks

Swatting adults never ends it. A female lays hundreds of eggs and larvae mature in about a week, so if flies keep appearing then something within a short distance is producing them — and finding that is the entire job.

What actually works

Find and remove the breeding material: bins that need washing rather than just emptying, pet waste, a blocked drain, or a dead animal in a wall or attic. Fit and repair screens and use tight-lidded bins. Traps and sprays only ever manage the adults.

Common questions

How do I tell a house fly from a drain fly?

Drain flies are much smaller, furry and moth-like, and hold their wings over the body like a tent.

How do I tell a house fly from a mosquito?

Mosquitoes have long trailing legs, narrow scaled wings and a forward-projecting piercing mouthpart.

Where are house fly usually found in a home?s

Kitchens, and around bins inside and out Anywhere organic matter is decomposing — compost, pet waste, a neglected drain Sunny windows, where they collect trying to get out.

Is a house fly dangerous?

They move between waste and food surfaces and carry contamination on their bodies. They do not bite.

Identification guidance only. Under Texas law, applying pest control treatments for hire requires a licence from the Texas Department of Agriculture. This page describes what a pest looks like — it is not a diagnosis of your property or a treatment recommendation for it.