According to Prous et al, 2019, there is currently no reliable key or species treatment available for this genus. The description follows Benson (Priophorus ulmi).
The head on the frons and temples above smooth and shining without sculpture or hair-warts. Cladius rufipes is a black sawfly with yellowish tibiae and tarsi on all legs. The wings are more or less infuscated. The abdomen has a brown spot in the middle of the first tergite.
Larvae feed on elm.
Size: 5 - 7.5mm
Distribution: England, Scotland, Ireland
Flight period: Bivoltine, May to August
Plant associations: Ulmus spp. (elms)
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
Prous, M., Liston, A., Kramp, K., Savina, H., Vårdal, H. and Taeger, A., 2019. The West Palaearctic genera of Nematinae (Hymenoptera, Tenthredinidae). ZooKeys, 875, p.63.