Cimbex femoratus - Birch Clubhorn

Found throughout the whole of Britain with the exception of Shetland, Orkney and the Outer Hebrides (Musgrove, 2022).

Usually a black, or reddish-brown bodied insect, though very rarely yellow forms occur. Males may have a red banded abdomen. The wings in both sexes have a clearly defined fuscous apical band. The pale cream membrane in the centre of the first tergite contrasts strikingly with the dark sclerotised portion. The yellow forms can be confused with Cimbex luteus and Cimbex connatus but only femoratus has clearly defined, dark, apical bands on the fore wings.

Larvae feed on birches.

Jump to other Cimbicidae

Size: 20 - 28mm

GB IUCN Status:Least Concern
GB Rarity Status:None

Distribution: England, Scotland, Wales, Ireland

Flight period: May to August

Plant associations: Betula spp. (birches)


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.

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 Natural England, unpublished