Sirex juvencus (Linnaeus, 1758)

Sirex juvencus

Females have reddish to yellow legs including the apical tarsal segments of all legs. The head and thorax are blue-black and the abdomen is dark brown. Basal antennal segments are often reddish brown with the remainder black.
Males are similar to the female but are banded in yellow on middle tergites and always with basal antennal segments reddish brown. Hind legs in the male are darker but with the apical tarsal segments still pale.

Larvae feed in timber of conifers for up to 3 years.


Size: 10 - 40mm

Status: Common

Distribution: England, Scotland, Wales

Flight period: June to October

Plant associations: Pinaceae spp. (firs, larches, spruces and pines)


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., Goulet, H., Smith, D.R., Boudreault, C., Wilson, A.D. and Scheffler, B.E., 2012. Siricidae (Hymenoptera: Symphyta: Siricoidea) of the western hemisphere. Canadian Journal of Arthropod Identification 21: 1-305, 21, pp.1-305.