The adults are similar to the house fly, except they are somewhat larger,
without stripes, and yellowish hairs on the thorax. The adults appear in
attics, wall voids and at windows during the winter.
(Pollenia rudis) The maggots feed on earthworms during the spring and
summer, the complete their development in about 30 days. The adults of
the last generation overwinter in large numbers in attics and wall voids.
They may be active during the winter, but leave the house in early spring.
Sealing outside cracks and crevices around soffits and shingles may help reduce numbers; spraying in attics during late fall and winter may reduce the adults inside.