House fly vs Lesser house fly
These two are easy to mix up. Here's how to tell a house fly from a lesser house fly, and whether either one bites or stings.
House fly
Musca domestica
Lesser house fly
Fannia canicularis
≠The key differences
House fly is generally larger and stouter with broader abdomen and different flight (more direct). Musca has more pronounced thoracic striping and different wing venation.
⚖︎Side by side
| House fly | Lesser house fly | |
|---|---|---|
| To humans | Disease vector | Mechanical vector |
| Size | 6-7 mm body length | 3.5-6 mm body length |
| Colours | Gray, Dark gray / black, Yellow-gray, Reddish brown (eyes) | Grey, Black, Pale yellow-brown (legs) |
| Family | Muscidae | Fanniidae |
| Habitat | Human dwellings, farm buildings, garbage dumps, compost piles, manure and other decaying organic material. | Human dwellings, garbage areas, compost heaps, animal housing, farms and gardens with decaying organic matter |
| Range | Cosmopolitan — found worldwide wherever humans or domestic animals occur. | Cosmopolitan in temperate regions worldwide; common across Europe, North America and other inhabited regions |
| Active | Active year-round in warm climates; spring to autumn in temperate zones; mostly daytime (diurnal). | Year-round in heated buildings; outdoors most active in spring to autumn and during daylight hours |
| Pest? | Yes | Yes |
🔍How to spot a house fly
- Gray thorax with four dark longitudinal stripes (more visible from above).
- Red-brown compound eyes (closer together in males) and slightly checkerboarded abdomen.
- Body length about 6-7 mm; sponging mouthparts and characteristic wing venation of Muscidae.
- Habit of resting on vertical surfaces and walking on food items while feeding with white saliva-like regurgitate sometimes visible.
🔍How to spot a lesser house fly
- Small slender fly 3.5-6 mm long (smaller than Musca domestica)
- Distinctive short, looping flights and tendency to hover in the centre of a room or over ceilings
- Narrow elongated abdomen with faint banding and a grey thorax with subtle longitudinal lines
- Males patrol in angular loops below light fixtures and seldom land on food; when resting they choose ceilings, cords and light fittings.
?Frequently asked questions
What is the difference between a house fly and a lesser house fly?
House fly is generally larger and stouter with broader abdomen and different flight (more direct). Musca has more pronounced thoracic striping and different wing venation.
Is a house fly or a lesser house fly more dangerous?
House fly: Disease vector. Lesser house fly: Mechanical vector. House flies do not bite to feed, but they can contaminate food and surfaces with bacteria, protozoa and viruses picked up from waste and animal matter. Lesser house flies do not bite or sting and are not venomous.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.