Recorded locally in England and Wales north to Yorkshire, although very sparsely in south Wales and south-west England at time of writing. Historic records may refer to Caliroa tremulae, which was not included in Benson (1952). However, most recent records appear to have been made in the light of this knowledge (Musgrove, 2023).
A black insect. The third antennal segment clearly shorter than the fourth and fifth combined. Hind tibia yellow-brown basally. Hind tarsus may be weakly yellow-brown basally. Middle tibia marked with yellow-brown on the external face in males and basally in females. On the hind wing, the females have two enclosed cells, whilst the males have none but possess a peripheral vein.
Caliroa varipes larvae are mucus covered " slugworms" that feed on the leaves of various trees. They pupate in the ground.
Size: 4 - 6mm
GB IUCN Status: Least Concern
GB Rarity Status: None
Distribution: England, Wales, Ireland
Flight period: Bivoltine, May to June and August
Plant associations: Populus spp., Salix spp., Betula spp., and Quercus spp. (poplars, willows, birches and oaks.)
Benson, R.B., (1952). Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Lacourt, J. (2002). Révision des Caliroa Costa ouest-paléarctiques (Hymenoptera, Tenthredinidae). - Revue française d'Entomologie, (N. S.), Paris 24(3): 125-131
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. 2023. A review of the status of sawflies of Great Britain - Phase 2: The Athaliidae and the Tenthredinidae (excluding Nematinae). Natural England, unpublished