Face fly females (6–10 mm) have a dull gray thorax with four thoracic stripes (Williams 2009) and sponging mouthparts used to ingest fluids. The female (left) has a wider vertex between compound eyes, and darkly checkered abdomen that is gray-black, except for the first abdominal tergite which has yellow patches at its lateroventral margins. The male (right) has a shiny black thorax, a narrower vertex, and a bright golden abdomen starting at the second segment with one black stripe down the middle. Both sexes have a sharply curved M1 wing vein (arrows), characteristic of Musca spp., and distinctive tufts of setae on alary sclerites ventral to wing bases and tiny setae (‘hairs’) between the 1st thoracic spiracle and the head (Loomis et al. 1971). Photo credit: Matt Bertone.