Nymph: Single tailed, strout brownish body with yellow markings. Large powerful jaws
Imago: Dar, soft bodied with almost black head and legs. Four shiny, hard wings which are heavily veined. The wings are held roof-shaped when at rest. The alderfly has long jointed antennae
Margins of ponds, lakes and rivers
Sialis Lutaroa is the most common Alderfly, during May and June they can be found in large numbers. They are not strong fliers and spend much of their time crawling around the waters edge on plants and stones or resting.