Cluster Fly

Color: Non-metallic, light and dark gray areas on abdomen

Size: About 5/16 inch long

Feeding & Habits: Feed on earthworm matter in lawns and ground cover. Adults of the last generation of the year become numerous during the latter days of September to mid-October. As cold weather progresses, adults seek protected places to spend the winter. In many cases, this is within walls, attics, storage rooms, and basements of houses. Screens offer no protection since these flies prefer to crawl in through small openings elsewhere around the building. For this reason they are extremely difficult to keep out of houses. Isolated houses in the country are especially prone to invasion, since they offer the only warm shelter for miles around.