Similar to P. albopictus and pale forms of P. varius.
Females have a yellow head with large black patterns. The thorax is black with yellow markings including on the mesoscutum, mesoscutellum and metascutellum. Abdomen is orange-brown above with only tergites 1 and 2 and the lateral margins marked with black. Venation brown and with a brownish yellow stigma.
Males have a head that is anteriorly yellow and posteriorly black with yellow stripes from the eye to the back of the head. The thorax is mostly black with the mesoscutellum and sometimes metascutellum yellow. Abdomen and venation as per the female.
Larvae feed in leaf rolls or twists on common alder and grey alder (on the continent). Pre-pupae have been known to rest for four winters before emerging.
Size: 8 - 11mm
Status: Fairly common, widespread.
Distribution: England, Scotland, Wales, Ireland
Flight period: May to June
Plant associations: Alnus spp. incl. Alnus glutinosa and Alnus incana (alders)
The National Biodiversity Network records are shown on the map below. (See terms and conditions)
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