Arachnospila trivialis is a widespread spider wasp of sandy soil areas of the Palaearctic.

The males have a quite distinctive genital plate, but females are very similar to other species assigned to the subgenus Ammosphex, such as A. anceps and considerable care is required to identify them.

[2] Northern and central Europe, including southern and western areas of Great Britain, and across Asia to the Pacific.

Apparently little appears to be known about A trivialis nesting biology, but like other Arachnospila species it is likely to excavate a nest in loose sand having already paralysed a spider and concealed it in nearby vegetation.

Adults have been observed to visit the flowers of wild parsnip.