Acanthocnema glaucescens (Loew, 1864)

A species which can be swept from mossy boulders in shady streams, usually, but not exclusively, in woodland. It has been found in the splash zone of a small waterfall on open moorland at Moorhouse NNR. Most often recorded from western Britain where this habitat is most frequent, but Hinton (1981) found adults to be common in early spring in southern England. Hinton (1981)[1] found larvae living in, and feeding on, the egg masses of caddis flies and some Nematocerous Diptera (e.g. Dixidae) and Nelson (1992)[2] describes the larvae and pupae. He found about 30 larvae in caddis egg masses laid under a piece of wood trapped between two stones and two pupae in the algal film growing over the same stones. This has been considered to be a scarce species. However, experience during recent Dipterists summer field meetings suggest that it is widespread where suitable habitat occurs, but is unlikely to be encountered unless specifically searched for by sweeping over, boulders in streams and rivers. It is therefore usually overlooked. Adults from April to September, most frequent in Spring (Nelson, 1992)[2].

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