Capsid Bugs

On the underside of a leaf of a poplar tree: four green capsid bugs, probably Neolygus populi (Hemiptera: Miridae). There are several capsid bugs that look very similar to this but N. populi seems to be the only one associated with poplar trees.
Photo taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2010-06-12.