Chalcosyrphus eunotus

A medium-sized, brownish hoverfly superficially resembling Brachypalpus laphriformis, but the thorax is dull with faint stripes and the abdomen is broader with pairs of narrowly separated squarish grey patches on tergite 2 (male) and tergites 2 and 3 (female). It is much larger than C. nemorum and with much hairier legs, but the two species often occur together, so care is necessary.

Good quality images are required showing the identifying features. It may not be possible to confirm some records without suitable images.

Adults can be observed resting on fallen timber at the edge of streams, on log jams, or sunbathing on nearby foliage. Males are territorial and will attack passing insects. Adults rarely visit flowers.

Adults fly from April to July but seem to peak in late April and early May.

The larvae develop in partially submerged fallen logs and branches in streams, especially where log jams have formed. This is nearly always in wooded streams with dappled sunlight and lush streamside vegetation (e.g. Stinging Nettle or Butterbur beds).

Chalcosyrphus eunotus is scarce but possibly under-recorded with records confined to southern Britain especially the West Midlands and Welsh Marches. Graded Nationally Scarce by Ball & Morris (2014, JNCC Species Status No. 9).

Rarely recorded in Leicestershire and Rutland.