Water Measurer - Hydrometra stagnorum


Length about 13mm. It has a very long, thin head, a slender body and its antennae resemble a fourth pair of legs. Usually wingless but occasionally fully winged. It often has a dark greyish or even black appearance.

Identification difficulty

Ditches, ponds and slow moving streams. Found at vegetated margins of all types of water body, providing there are vertical emergent plant stems available as egg-laying sites.

When to see it

The adult moves slowly across the water surface in search of prey, lying just below, or in the surface film, it feeds on mosquito larvae and water fleas which it spears through the surface film. It will jump if disturbed.

UK Status

Distributed throughout Britain though commoner in the south.

VC55 Status

Fairly common in Leicestershire and Rutland.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map