Eristalis cryptarum is a European species of hoverfly

Hoverfly

Hoverflies, sometimes called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the larvae eat a wide range of foods...

. Known as the bog hoverfly, it only lives in and around wet heathland and valley mires. Its larvae are assumed to live in peat that is saturated with water, such as that found in these boggy areas.

The hoverfly has a wide distribution across central and northern Europe, including Siberia. In England, it was once found in all southwestern counties as far east as the New Forest

New Forest

The New Forest is an area of southern England which includes the largest remaining tracts of unenclosed pasture land, heathland and forest in the heavily-populated south east of England. It covers south-west Hampshire and extends into south-east Wiltshire....

, but since the middle of the 20th century its range has contracted, for unknown reasons, and it is only now found at a few sites on Dartmoor

Dartmoor

Dartmoor is an area of moorland in south Devon, England. Protected by National Park status, it covers .The granite upland dates from the Carboniferous period of geological history. The moorland is capped with many exposed granite hilltops known as tors, providing habitats for Dartmoor wildlife. The...

, Devon. In Denmark it is considered critically endangered, possibly extinct.