About Sialis lutaria (Linnaeus, 1758)
Adults of Sialis lutaria can reach a body length of 20 millimetres (0.79 in), with a wingspan ranging from 22 to 34 millimetres (0.87–1.34 in). They have a stocky body that is primarily black or dark brown, including the head and legs. Their wings are greyish, membranous, and translucent, with distinct dark veins. When at rest, the wings are held in a roof-like position over the body. Mature flat larvae grow to approximately 17 millimetres (0.67 in) long. Larvae have large heads, powerful jaws, and three pairs of legs. They also have feathery gills on each abdominal segment, and their abdomen ends in a single long gill. This species occurs mainly in Austria, Belgium, the United Kingdom, the Czech Republic, France, Germany, Italy, the Netherlands, Spain, Poland, Romania, and Switzerland. Adult Sialis lutaria typically live in ponds and slow-flowing streams, while the larvae live underwater in mud and detritus.
