Scientific Name: Pollen rudis
Description: Cluster flies are close relatives of blow flies and are similar in size to house flies, approximately 3/8”. But have a more robust structure. They are non-metallic gray, lack stripes on the thorax, and have yellow or golden hairs on the top, behind the head, and around the base of the wings. Cluster flies appear narrow when at rest because their wings completely fold over their back. The larvae typically are spindle-shaped maggots, but are never seen because they develop as parasites in earthworms.