Alderfly  (Sialis lutaria)

Description

Alderflies are fairly primitive insects, and were the first insect group to develop a pupal stage(4). The robust body is brown or black, with two pairs of brown or grey wings, which are folded back over the body when at rest and feature dark veins. The larvae are aquatic and have large heads with powerful jaws; there are three pairs of legs and then a pair of limb-like feathery gills on each segment of the body, except the very last segment which is tipped with a long spike-like gill (3).

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