This is quite a brightly coloured sawfly which I often see in my garden during the spring and summer months. They grow up to 7mm (0.3in) long, and are seen around the plant Bugle Ajuga reptans, which is one of the plants the larvae feed on. The commonest of the Athalia and widespread in Britain. Often seen in gardens.
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August 2017, rear garden, Staffordshire, England.