How to Identify Indoor and Outdoor Flies

Most flies remain outdoors in wooded areas, or near lakes and stagnant water, and are commonly referred to as outdoor flies. Others are attracted to homes and offices due to the presence of sewage, garbage, or pets, and are known as indoor flies. Both indoor and outdoor flies have specific traits adapted to suit their environments, and you can use these to distinguish them from each other. Knowing how to spot these differences can help you identify indoor and outdoor flies.

Things You'll Need

  • Fly trap
  • Tape measurer
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Instructions

  1. Outdoor Flies

    • 1

      Capture the flies in question by placing a fly trap 2 feet high.

    • 2

      Examine the bodies of the flies. If their abdomens are brown or orange, they are face flies.

    • 3

      Look at the head of the flies. If their mouths have thin, sharp beaks protruding from them, they are stable flies.

    • 4

      Use the tape measurer to ascertain the length of the flies. If they are small with black bodies, bear a similar resemblance to mosquitoes and measure between 1/16 to 1/8 inches long, the flies are fungus gnats.

    • 5

      Observe the wings of the flies. If they are covered with many fine hairs that make them look fuzzy and enclose the bodies of the flies in a roof-like manner they are moth flies, also known as drain flies.

    Indoor Flies

    • 6

      Capture the flies in question by placing a fly trap 3 to 8 feet high, depending on the size and area of the room.

    • 7

      Look at the mouth and thorax of the flies. If there are sponge-like proboscis protruding from their mouths and four dark, vertical stripes across their backs, they are house flies.

    • 8

      Study the coloring of the flies. If they have a metallic black, blue, green or copper appearance, the flies are either bottle or blow flies. You can distinguish the flies only by their larvae; bottle fly larvae hatch within two to three days, while blow fly larvae hatch within six to 48 hours.

    • 9

      Examine the neck and abdomen of the flies. If the thorax is tan and the back of the abdomen is black while the underbelly is gray, the flies are fruit flies.