[1][2] Tenthredo arcuata can reach a length of about 8–10 millimetres (0.31–0.39 in).

These sawflies have a yellow to apple green body with black head and thorax .

The upperside of the abdomen shows greeny-yellow and black bands.

[3] The adults can be encountered from April through July, feeding on small insects and on nectar and pollen of flowers (especially on Apiaceae species, on Polygonum bistorta, Tanacetum vulgare and Viburnum opulus).

The larvae feed at night on leaves of Trifolium repens and Lotus corniculatus.