A very tiny (2 - 4 mm) yellow fly with three dark stripes on the thorax, and a dark triangular patch on the head. There are many other very similar flies in the family so microscopic examination is necessary to identify the species. See ID guidance below for detailed features to look for on C. pumilionis.

Chlorops pumilionis has the following features:

• 2-4mm (but smaller specimens to 1.2mm are possible)
• the black stripes on the thorax are not shining (dull due to dusting)
• the black triangle on the frons extends two-thirds the length, ha slightly sinuous sides and usually a groove along the mid-line at the front
• arista is black and more or less bare
• face is yellow
• there are short bristles on antennal segment 3
• the black mark on the sternopleuron is completely dusted
• ends of the tarsi are darkened

Around grasses and cereal crops, or nectaring on various plants.

Adults from overwintering larvae hatch from mid May onwards, followed by a second generation that may persist until October.

Cylindrical cream-colored larvae reach up to 7 mm. The species overwinters in the larval stage in wild grasses and cereal crops.

Widespread and fairly frequent in England.

Status in Leicestershire and Rutland is not known.