This is generally a more yellow/green based corixidae and can be picked out as such from other species in your tray. At 6mm it is of medium size and all Cymatianidae have a brown pronotum with no transverse yellow lines. It is a local species and while can be found across Northants it is not in high numbers and tends to be in smaller concentrations/colonies. It is a more a lowland species and is found over bare substrate usually muddy or clay next to a weedy habitat that it can use for cover. It likes small wave washed shores on some of the gravel pits in Northants. It has been said that it is found in Acid habitats although it is tolerant of a wide variety of PH values (TH, 2003). They over winter as adults and can hibernate during winter, they have one brood a year and mate in May-June.  

Distribution:

In Northants it is found in 10 of the 45 10km squares and just 20 sites being a scarce species. 

Habitat:

Recent studies (NWG, 2008) have found that it occurs in lowland areas and prefers a high water temperature, rich aquatic vegetation, sediments of clay, and a small wave action. It appears to be tolerant of PH and can occur in acidic locations.

Identification:

For corixidae with plain brown pronotum's there are three species in the group however Cymatia coleoptera is much smaller at 3.7mm and Cymatia rogenhoferi larger at 7.2mm and is still here in the British Isles.