Strongylogaster macula - Blemished Fern-sawfly

Widespread but local throughout much of Britain (Musgrove, 2023).

The smallest of the Strongylogaster species. The thorax is black with a predominantly orange-yellow abdomen (dark at the base and apical tergites in the female). The orange tergites 2 to 5 on the female are often contiguous with yellow marks on the lateral faces. Clypeus and labrum are white. Femora are usually red and at least the front four are red in the male.

Strongylogaster macula larvae feed on ferns.

Jump to other Strongylogaster species

Size: Approx 5 - 7mm

GB IUCN Status: Least Concern
GB Rarity Status: None

Distribution: England, Scotland, Wales, Ireland

Flight period: May to June

Plant associations: Athyrium filix-femina (lady fern), Pteridium aquilinum (bracken), etc.


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. 2023. A review of the status of sawflies of Great Britain - Phase 2: The Athaliidae and the Tenthredinidae (excluding Nematinae). Natural England, unpublished