Cluster Flies

General Descriptions
Not associated with filth, these flies are unusual in that they lay eggs on earthworms which the larvae consume. In the fall, adult cluster flies become pests when they invade homes, especially attics, for a warm, sheltered spot in which to spend the winter. They resemble house flies, but hold their wings parallel to the body, not in a triangular configuration as house flies do. Cluster flies are approximately one-fourth of an inch long, covered with fine golden hairs, and have no stripes on the thorax.

General Control
Unlike other filth flies, the principal means of controlling cluster flies is exclusion, that is, sealing buildings to prevent their entry.