Chalcosyrphus nemorum
Chalcosyrphus nemorum is a Palearctic and Nearctic species of hoverfly. Description. External images For terms see Morphology of Diptera Wing length 6.5-8.25 mm. Hind femora are swollen and deep. Hind tibiae strongly curved and the ventral surface with closely-set short black hairs for the whole length. The abdomen is short tergites 2-4 with a pair of pink or orange-brown marks. The legs are black with yellow knees and yellow tarsi. Distribution. Fennoscandia South to the Pyrenees and from Ireland East through Northern, Central and Southern Europe (to South Italy) across the Palearctic into Russia  and the Russian Far East and Sakhalin and Japan. In the Nearctic from Alaska to Nova Scotia and South to California. Biology. The habitat is forest wetland ("Alnus" - "Salix" carr, deciduous forest and woodland with streams). Adults frequent sunlit foliage of bushes on trunks of fallen trees beside water and settle on damp mud at the water's edge. Flowers visited include white umbellifers, "Caltha", "Anemone nemorosa", "Euphorbia amygdaloides", "Ranunculus", "Rubus idaeus", "Potentilla erecta", "Sorbus aucuparia"and "Taraxacum". Flies from the beginning of May to the end of September.