Janus luteipes - Yellow-legged Stem-sawfly

One of three species of Janus in Britain. Records are sparsely but widely distributed around southern England, north to Cheshire, with a single old record from south Wales. The species is still being recorded occasionally to the present, but this seems to be a species that is present at low density and/or very unobtrusive (Musgrove, 2022). The tegulae are black or brown and the pronotum is edged with white behind. In Janus cynosbati, the tegulae are yellow and the pronotum is not edged with white.

Janus luteipes larvae feed inside the shoots of willows, poplars, etc.

Jump to other Cephidae

Size: 6 - 9mm.

GB IUCN Status: Least Concern
GB Rarity Status: Nationally Scarce

Distribution: England, Wales

Flight period: May to July

Plant associations: Salix spp. (willows) and Populus spp. (poplars) including Populus tremula (Aspen), Viburnum spp. (Wayfarer, Guelder Rose)

References:

Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London

Lacourt J., 2020. Hymenoptera of Europe 2. Sawflies of Europe. NAP Editions.

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

Liston, A., 1995. Compendium of European Sawflies, Chalastos Forestry, Daibersdorf

Musgrove, A.J. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished