Benson (1952) was not aware of records subsequent to those from Wicken Fen in the late 19th or early 20th century. Subsequent records found in a range of databases have all been confirmed to be erroneous based on a taxonomic error in some biological recording software (Musgrove, 2023).
A very dark species almost entirely black all over except for the more or less yellowish hind margin of the pronotum, tibiae and apical margins of tergites three to five. Wings infuscate especially at the apices.
Tenthredo neobesa larvae feed on sowthistles.
Size: 11 - 13mm
GB IUCN Status: Regionally Extinct
GB Rarity Status: Extinct
Flight period: June to July
Plant associations: Sonchus arvensis (sowthistle)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Fekete, K. (2018) Beginner’s guide to identifying British Tenthredo, Natural History Museum, London. http://www.nhm.ac.uk/content/dam/nhmwww/take-part/identification-trainers/sawflies-guide-id-trainees.pdf [Accessed 26Apr2019]
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
Musgrove, A.J. 2023. A review of the status of sawflies of Great Britain - Phase 2: The Athaliidae and the Tenthredinidae (excluding Nematinae). Natural England, unpublished