Platycheirus coerulescens, the Hooked Sedgesitter, is a species of syrphid fly in the family Syrphidae.
For terminology Speight key to genera and glossary
The thoracic pile of the insect is completely white, while the fore and mid femurs are orange in color. On the apical part of the fore femurs, there is a row of 9-12 strong, straight, black posterior setae, which are approximately twice as long as the diameter of the femur; this row ends in a single longer seta with a strongly curved apex at the apex of the row. Additionally, there is a row of 3-5 strong yellow ventral setae on the basal third of the fore femur, and these setae are slightly shorter than the femoral diameter. On the basal third of the mid femur, there is a row of 2-5 long strong, yellow or black anteroventral setae, and the longest of these setae is approximately twice the femoral diameter. The wings are mostly bare on the basal half. The spots of the tergites are orange, dull yellow, or entirely grey, and they are always overlaid with strong silvery pollinosity. [1]