Nematus brischkei (formerly Craesus brischkei)
One of four Nematus species in Britain and Ireland characterised by the enlarged basitarsal segment. This species has only been recorded in England in mid-Bedfordshire around 1948 to 1950 where it was initially reared from a larva. This species is shining in the centre of the upper part of the mesopleura with the punctures clearly discernible amongst very fine microsculpture (Nematus alniasti lacks microsculpture here). The femora are mainly black. Males are unknown.
Nematus brischkei larvae are solitary feeders (at least in late instars) on hornbeam and hazel.
Size: 7 to 8mm
Flight period: May to June
Plant associations: Carpinus spp. and Corylus spp. (hornbeams and hazels)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Chambers, V. H. 1950: Croesus brischkei Zaddach, a sawfly (Hym., Tenthredinidae) new to Great Britain. - The Entomologist's Monthly Magazine, Fourth Series, London 86(11): 85-86
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