Adult cluster flies resemble house flies, but are slightly larger, about 5/16 inch long, narrower and nonmetallic gray. When at rest, they overlap their wings at the tips, whereas the house fly does not. Also, the thorax is without distinct stripes, contains many short, yellow-golden hairs, and the dark gray abdomen is hairy with light and dark patches of color. When crushed, the cluster fly has an odor resembling "buckwheat honey." - BugGuide.net
yard, Newburyport, MA
https://bugguide.net/node/view/258054