Adults are slightly larger than house flies (Musca domestica), dull grey with black markings and golden-yellow hairs on thorax. The hairs are more numerous on the underside, near the legs. See (1) for photo key to species occurring in North America.
The immature stages, eggs and larvae, are are seldom seen because they are deposited on the soil and they burrow into earthworms which they parasitize. Maggots are cream colored, elongated and wedge shaped.
Probably from Europe. They may have found their way to America in the ballast of ships containing soil, probably along with introduced earthworms.
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