This is an uncommon bug in northants as it is perhaps a more Northern species. Savage associated it with upland lakes, at altitudes >300m, and stony lakes with a deep littoral zone (AAS, 1989). For more southern species it has been found in open water with no submerged macrophytes in sand or silt ponds (JD, 2007) sometimes weakly saline. Often with the preceding or with Glaenocorisa propinqua in large peat pools, but also on sandy substrata in calcareous lakes (TTM, 1956). In Ireland it was found in two distinct lake types - base poor upland lakes and eutrophic lowland lakes (BN, 1995).

The asymmetrical eggs are laid in mid-April in southern England by overwintered females.

Distribution:

This has only been found in 3 sites across Northants, although there is one extra record on the NBN gateway that still needs to be validated. One was by the environment agency from Slade brook in 1993, one from Dogsthorpe Starpit (slightly saline) and Sandy Lane road balance pond in 2012 by me. As the name suggests this was a sand over clay pond recently created to support the water run off from a new road.

Habitat:

In Northants appears to favour sand or silt ponds with little or no vegetation. Also tolerates some salinity including road salt run off.

Identification:

This is a large corixid that can be between 7.5mm and 10mm. The pronotum has a midline ridge (keel that runs from the front to almost the hind margin. The mid femora has long hairs along its entire lower edge.