Trichiosoma pusillum - Small Hairy-clubhorn
A black sawfly within the tibiale group of very similar Trichiosoma species. Rare and known only from the type specimen from 1835. Quinlan & Gauld (1981) synonymised pusillum (and many other taxa) within lucorum. Viitasaari (1989) examined the type specimen in the BMNH and said it should be synonymised with Russian nigripes but also noted it may just be a dwarf example of tibiale (Musgrove, 2022).
Trichiosoma pusillum larvae feed on willows.
Size: 13 - 24mm
GB IUCN Status: Data Deficient
GB Rarity Status: Unclear
Flight period: May to June
Plant associations: Salix spp. (willows)
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
Musgrove, A.J. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished
Quinlan, J. & Gauld, I. D. 1981: Handbooks for the Identification of British Insects. Hymenoptera, Symphyta (except Tenthredinidae) Vol 6, Section 2a (New edition), Royal Entomological Society, London.
Viitasaari, M. 1989: Taxonomic notes on the genus Trichiosoma Leach (Hymenoptera, Cimbicidae) II. - Annales Entomologici Fennici, Helsinki 55 (3): 111-129