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Extension > Garden > Diagnose a problem > What insect is this? > Insects found indoors > Winged Insects - 1/4 inch up to 1/2 inch > Blow flies, Family Calliphoridae

Photo Credit: Jeff Hahn, University of Minnesota#alt-2
Photo Credit: Jeff Hahn, University of Minnesota
Blow flies, Family Calliphoridae
Size: 1/4 - 1/2 inch long
Description: House fly-like; bodies are metallic green or gold

Where/When: Typically an outdoor insect. They are sometimes found indoors during the summer, as well as occasionally during the fall

Significance: Blow flies are usually associated with decaying animals, excrement, or other sources of decaying organic matter. When found indoors during the summer, especially when large numbers suddenly appear, they are probably associated with a dead animal in a wall void, attic, or similar place.

Small numbers of blow flies may enter buildings in the fall and become a nuisance. Since blow flies are associated with waste and decaying matter, they can potentially be a vector of disease-causing bacteria. Blow flies do not bite.

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