Have you ever wondered why the abbreviation ‘agg.’ is used after the scientific names of some flora and fauna? Well, this particular sawfly is a prime example.
‘Agg.’ is short for aggregate and is used where there exists a group of species that are so closely related and difficult to distinguish from each other, that for practical biodiversity recording purposes they are considered one species. As the Nature Spot website explains
The four species within the Tenthredo arcuata complex are problematic to distinguish and the species boundaries are unclear. The complex within Britain and Ireland consists of the species T. arcuata, brevicornis, notha and schaefferi. Unless specimens have been microscopically examined by someone with suitable expertise, we have decided that they should be recorded as part of this aggregate.
So, the scientific name used for this rather cute little sawfly is quite a mouthful: Tenthredo arcuata/brevicornis/notha/schaefferi agg.