Sirex torvus

This is a species of Central European origin and is not thought to be the same species at S. cyaneus. Sirex torvus females have the sawsheath longer than the basal plate (as described in Benson) whereas S. cyaneus has the sawsheath equal in length to the basal plate.

The female is blue-black with reddish yellow legs and is similar to S. juvencus. However, the basal segments of the antennae are always black.

Males differ from the female in having darker hind legs and an abdomen that is reddish brown from tergite 3 to the apex.

Sirex torvus larvae feed in the timber of fir trees for up to 3 years.

Jump to other Sirex species

Size: 10 - 40mm

Status: Occasional

Distribution: England, Scotland, Wales, Ireland

Flight period: June to October

Plant associations: Abies spp. (firs)


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.

Schiff, N. M., Valley, S. A., LaBonte, J. R. and Smith, D. R. (2006) 'Guide to the siricid woodwasps of North America.' Forest Service, Forest Health Technology Enterprise Team. USDA, Morgantown

Viitasaari, M. & Midtgaard, F. 1989: A contribution to the taxonomy of horntails with notes on the genus Sirex Linnaeus (Hymenoptera, Siricidae). - Annales Entomologici Fennici, Helsinki 55(3): 103-110