Three predominantly black and white Pachyprotasis species in Britain and Ireland can cause confusion; rapae, variegata and simulans.
Females of variegata are readily distinguished through having a red hind femora and tibia. Males are more difficult to separate. Males of variegata and similans lack a diagonal black stripe on the mesopleura (present in rapae) though the mesopleural margins may be darkened and there is a black band where the mesopleuron meets the mesosternum. The frons in variegata is dull with fine coriaceous sculpture between dense but shallow punctures (shining with only faint sculpture in simulans).
Larvae probably feed on a wide range of herbaceous plants but have been found on potato crops and on the continent on foxgloves.
Size: 8 - 9mm
Distribution: England, Scotland, Wales
Flight period: May to June
Plant associations: Solanum tuberosum, Digitalis sp. and probably a wide range of others (potatoes, foxglove)
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