Hemichroa crocea - Orange Bicolorous Sawfly

North to Orkney, seemingly common and widespread (Musgrove, 2024).

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.

Jump to other Hemichroa species

Size: Female: 5 - 8mm, male: 5 - 6mm

GB IUCN status: Least Concern
GB rarity status: None

Distribution: England, Scotland, Wales, Ireland

Flight period: Multivoltine, May to September

Plant associations: Alnus spp., Betula spp. and Corylus avellana (alders, birches and hazel)

The National Biodiversity Network records are shown on the map below. (See terms and conditions)

References:

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

Musgrove, A.J. 2024. A review of the status of sawflies of Great Britain - Phase 3: The Tenthredinidae (subfamily Nematinae). Natural England, unpublished