Benson (1952) included scutellaris within nassata and so most workers will not have attempted to separate these two species. Indeed, males may not be separable (although Lacourt 2020 does so). Given that keys separating the females were published in 1998 and 2014, unsurprisingly the majority of records are recent (Musgrove, 2023).
As with all Tenthredopsis species Tenthredopsis scutellaris is variable in colour. The description given here follows Blank and Ritzau 1998 but it should be noted that British specimens may differ in colour from continental counterparts.
In the female the abdomen is broadly red, with the sixth tergite red on at least the basal margin. The hind tarsi are mostly dark but if the middle segments are pale, the first and fifth segments are usually also significantly pale. The hind coxae with a large whitish spot on the lateral face. The hypopygium centrally is triangular and only slightly indented at the apex (as for nassata).
The male cannot be reliably distinguished from Tenthredopsis nassata.
Larvae feed on grasses.
Size: Female: 8.5 - 11mm, male: 8 - 11mm.
GB IUCN Status: Data deficient
GB Rarity Status: None
Distribution: England, Scotland, Ireland
Flight period: May to August
Plant associations: Gramineae (grasses).
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Blank, S.M. and Ritzau, C., 1998. Die Tenthredopsini Deutschlands (Hymenoptera: Tenthredinidae). Pflanzenwespen Deutschlands (Hymenoptera, Symphyta). Kommentierte Bestandsaufnahme, pp.227-246.
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 Natural England, unpublished