The Ametastegia are a small genus of slender sawflies within the Empriini tribe. They are centred around the holarctic and the orient. In Britain and Ireland there are seven species which are divided into two subgenera Ametastegia and Protemphytus.
The genus Ametastegia are characterised by having the fore wing with a complete anal cell with an oblique cross vein (more erect than in Empria) and vein M and 1mcu near to parallel. In the hind wing vein cu-a joins vein 1A at an oblique angle and there is no enclosed cell M.
The larvae are free feeders, often gregariously, on herbaceous plants. Some species (eg. A. carpini) can be garden pests defoliating plants. Ametastegia glabrata burrows into soft material to overwinter as a pre-pupa and has been known to burrow into fence posts and timber building fascia boards including those treated with preservatives.
Benson's key to species given in part 2b of the Handbooks for the Identification of British Insects, volume 6 is still valid for the British and Irish species.
Ametastegia (Ametastegia) albipes (Thomson, 1871)
Ametastegia (Ametastegia) equiseti (Fallén, 1808)
Ametastegia (Ametastegia) glabrata (Fallén, 1808)
Ametastegia (Protemphytus) carpini (Hartig, 1837)
Ametastegia (Protemphytus) pallipes (Spinola, 1808)
Ametastegia (Protemphytus) perla (Klug, 1818)
Ametastegia (Protemphytus) tenera (Fallén, 1808)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Benson, R. B. 1959: The sawfly, Ametastegia glabrata (Fallen) (Hym., Tenthredinidae), damaging the timber of new schools in Warwickshire. - The Entomologist's Monthly Magazine, Fourth Series, London 95(20): 119
Cockcroft, R. & Berry, R. W. 1976: A note on the occurrence of Ametastegia glabrata (Fallen) in motorway fencing. - BWPA News Sheet 143: 1-3
Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168