Eristalis nemorum


Eristalis nemorum is a species of hoverfly. It is found in the Palearctic and in the Nearctic.

Technical description

For terms, see: Morphology of Diptera.
Wing length:. All tarsi are extensively black. Body-hairs are short. Arista plumose basal half. Densely dusted face has a black shining stripe. Hind femora are black in male. Wings are hyaline with quadrate brownish pterostigma. Body is yellow-haired. Hind metatarsi are darkened.
The male genitalia are figured by Hippa et al.. The larva is figured by Hartley.

Biology

The larvae are aquatic, and of the Rat-tailed maggot type. Adults are often seen visiting flowers. Flight period in the United Kingdom is from April to October, peaking around July and August. The males show a characteristic courtship display, hovering above a foraging female for minutes.
When many males are present two or more males may hover above one female.
Adult habitat is streamsides, fen meadow and poorly-drained pasture. Flowers visited include yellow composites, umbellifers, Cakile, Calluna vulgaris, Caltha, Cardamine, Cirsium, Crataegus, Eupatorium, Euphorbia, Filipendula, Malus, Menyanthes, Mentha, Parnassia, Prunus, Ranunculus, Rubus fruticosus, Salix, Sorbus, Succisa.