That's right Tim,.......
The bold highlighted portion describes the ones I always see here. When you see one and go to smash it, they run off to either side very swiftly without taking flight, just as it mentions below. They are a real pain in the ARSE in the warm months!..
PHORID FLY IDENTIFICATION
The phorids, also known as humpbacked flies, are small flies that resemble fruit flies in appearance.
They are usually tan to dark brown in color. The Phorid fly lacks the red eye color that is the classic trademark of the fruit fly.
Phorid flies are in the small category of flies, measuring up to 1/8 inch in length, including the wings.
The most prominent feature of this fly is the humpbacked shape of its thorax. The severe arch of the thorax gives it the common nickname of humpbacked fly.
A key indentifying trait is that the adult Phorid fly has a distinctive habit of running rapidly across surfaces instead of immediately flying when disturbed. Most flies immediately take flight.
Phorid flies are also know as coffin flies, when found in mortuaries and mausoleums.
Phorid flies have also been found to breed in poorly stored meats, damaged containers of moist foods, and organic-based glues and paints.
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"a snake in the grass is a GOOD thing" 
