Urocerus gigas - Giant Horntail

Long established and frequently encountered across Britain, north to Shetland, and Ireland. In both sexes the yellow eye spots are widely separated.

The female abdomen is banded with yellow. The hind tibia is only infuscated at the extreme apex which distinguishes it from Urocerus augur. The stigma is at least slightly darker than the costa and the ovipositor is clearly shorter than the fore wing.

In the male, the abdomen has the seventh tergite yellow.

Urocerus gigas larvae feed in the timber of coniferous trees and take 2 to 3 years to mature.

Jump to other Urocerus species

Size: 12 - 40mm

GB IUCN Status: Least Concern
GB Rarity Status: None

Distribution: England, Scotland, Wales, Ireland

Flight period: June to October

Plant associations: Pinaceae (coniferous trees) including Cedrus spp. (cedars), Chamaecyparis spp. (cypresses), Larix spp. (larches), Picea spp. (spruces), Picea abies (Norway Spruce), Picea sitchensis (Sitka Spruce), Pinus spp. (pines), Pinus sylvestris (Scots Pine), Pseudotsuga menziesii (Douglas Fir).


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

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 Natural England, unpublished

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.