In the female, the head, mesonotum and abdomen are orange-red. The antennae are entirely black as are the mouthparts, underside of the thorax and the first tergite and sawsheath. The legs are black on the coxae, base of femora and the apices of the tibiae and tarsal segments. The costa, the stigma and apical venation are brown with the basal venation being dark.
In the male, the antennae, head and thorax are all black. The abdomen is mainly piceous though some segments may be more or less orange or yellow. The tegulae are partially yellow and the legs more or less reddish-brown.
Hemichroa crocea larvae usually feed gregariously on the leaves of alder or birch and occasionally hazel.
Size: Female: 5 - 8mm, male: 5 - 6mm
Distribution: England, Scotland, Wales, Ireland
Flight period: Multivoltine, May to September
Plant associations: Alnus spp., Betula spp. and Corylus avellana (alders, birches and hazel)
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