Alderfly

Description

Sialis lutaria is a species of alderfly belonging to the order Megaloptera family Sialidae.This species is mainly present in Austria,Belgium,United Kingdom,Czech Republic,France,Germany,Italy,Spain,Poland,Romania and Switzerland.They have a stocky body with a black or dark brown basic coloration,including head and legs.The wings are greyish,membranous and translucent,with pronounced dark venation.At rest they are held roof-like over their body.Adults can reach 20 millimetres (0.79 in) of length and are most often encountered from May through June on vegetation near slow-flowing streams or close to ponds.The adults are bad fliers and never leave the waters where the larvae have developed.The flat larvae reach approximately 17 millimetres (0.67 in).They are aquatic predators of small invertebrates and usually wait for their prey in silt or under stones just emerging from the water.The life cycle in this species lasts about one-two years,but the adults live two-three days only,without feeding.