Mostly in the west and north of Britain and Ireland. In the female, the final 4 segments are adorned with closely adpressed silky white hairs giving a mouldy appearance. The male is difficult to separate from vitellinae but has a less rufous abdomen and with a less densely pubescent scutellum. The hind femur of the male has mostly dark hairs dorsally.
Trichiosoma sorbi larvae feed on mountain ash.
Size: 15 - 22mm
Distribution: England, Scotland, Wales, Ireland
Flight period: May to July
Plant associations: Sorbus aucuparia (mountain ash)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
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
Viitasaari, M. 1989: Taxonomic notes on the genus Trichiosoma Leach (Hymenoptera, Cimbicidae) II. - Annales Entomologici Fennici, Helsinki 55 (3): 111-129