Melanostoma dubiumMelanostoma dubium is a Palearctic species of hoverfly.DescriptionA small black fly, dark bronze or green bronze, with pale abdominal markings. It is hard to separate this species from other Melanostoma.Distribution and biologyFound from Fennoscandia south to the Pyrenees and from Scotland east through North Europe and the mountains Central Europe into European Russia and on through Siberia to Yakutia. The habitat is montane and alpine grassland and moor. Flowers visited include Carex, Potentilla erecta, Ranunculus. Flies from July to August dependent on altitude.