| Scientific name | Lucilia sericata |
|---|---|
| Group | Flies & Mosquitoes |
| Size | 8–12 mm (up to about 0.47 in) |
| Colors | Green, Blue and Metallic |
| Legs | 6 legs |
| Wings | Yes |
| Where found | Kitchen and Indoors, anywhere |
| Most active | Spring, Summer and Fall |
| Bites | No |
| Stings | No |
| Risk level | Nuisance |
How to identify it
The blow fly is a small member of the flies & mosquitoes group. Only one pair of flying wings; the hind pair is reduced to tiny knobs. Check for these three features:
- Metallic green, blue or bronze body
- Larger and louder than a house fly
- Often appears suddenly in large numbers indoors
About this bug
A shiny, metallic green or blue fly that lays eggs on dead animals, meat and garbage. A sudden swarm indoors often signals a dead mouse or bird in a wall or attic.
You'll usually find blow flies in the kitchen and indoors. They are most active in spring, summer and fall.
Is it dangerous?
Blow flies don't bite but can carry bacteria from rotting material.
Our rating: Nuisance, meaning it is a nuisance pest but not a health threat to most people.
When you'll see blow flies
Blow Flies are most active in spring, summer and fall. In spring, overwintering adults become active and many species lay their first eggs. Summer heat speeds up development, so populations can grow quickly. In fall, many bugs look for shelter, and some move toward or into buildings.
Typical places to check: kitchen and indoors, anywhere.
About flies & mosquitoes
The blow fly is one of the flies & mosquitoes. Flies have only one pair of working wings; the second pair is reduced to small balancing knobs called halteres. They go through complete metamorphosis, and the larvae, called maggots, need moist organic material such as garbage, soil, drain film or standing water.
Fly problems are almost always breeding-site problems. Finding and removing the moist material where larvae develop works far better than swatting adults.
What to do about it
- Search for and remove any dead animal, then clean the area
- Double-bag meat scraps and take trash out often
- Seal openings to attics and chimneys
Read the full guide: how to get rid of blow flies.
Bugs that look similar
Size: Blow Flies are larger, reaching 12 mm, while house flies top out around 7 mm.
Size: Horse Flies are larger, reaching 30 mm, while blow flies top out around 12 mm.
Frequently asked questions
What does a blow fly look like?
Metallic green, blue or bronze body. Adults measure 8–12 mm (up to about 0.47 in).
Does the blow fly bite or sting?
It does not bite. It does not sting. Blow flies don't bite but can carry bacteria from rotting material.
Where do blow flies live?
Blow Flies live in the kitchen and indoors.
When are blow flies most active?
Mostly in spring, summer and fall.