Globally, this genus has seven species distributed across the holarctic region. In Britain there are two species. The genus is absent from Ireland.
The genus Stethomostus can be characterised as follows. The pedicel of the antenna (second segment) is longer than it is wide and the first flagellomere is longer than the second. The post-genal carina is only developed for a short length below the level of the eye. The prepectus is presented as a raised shoulder and a furrow separates it from the mesepisternum. On the forelegs, the tibial spurs are bifurcate at their tips. The forewing has the stub-vein 2A+3A straight at the apex. The hindwing lacks the apical cross-vein m-cu such that cell M appears absent.
Larvae feed on Ranunculaceae.
Stethomostus fuliginosus (Schrank, 1781)
Stethomostus funereus (Klug, 1816)
Benson, R. B. 1939: Four new genera of British Sawflies (Hym., Symphyta). - The Entomologist's Monthly Magazine, Third Series, London 75(25): 110-113
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
Smith, D. R. 1969: Nearctic Sawflies. I. Blennocampinae: Adults and larvae (Hymenoptera: Tenthredinidae). - Technical Bulletin, U.S. Department of Agriculture, Washington 1397: 1-176
Togashi, I. 1984: The sawfly genus Stethomostus Benson in Japan (Hymenoptera: Tenthredinidae). - Transactions of the Shikoku Entomological Society, Matsuyama 16(3): 59-62