The Western Roundtail (Melanostoma mellinum) is a small, dusky-yellow and black, holarctic species. Identifiable by abdomen pattern. Males lack the flattening or broadening of the front legs characteristic of similar Sedgesitter (Platycheirus) males. Adults can be found on leaf surfaces where they feed on the pollen of grasses (Poaceae) and other wind-pollinated plants but also visit a variety of flowers. Larvae are entomophagous, mainly aphids.
Flight dates: April – July
Flowers: Rue Anemone, Dandelion, Wild Plum
Similar species: Platycheirus quadratus