Welted Lesser Mason Bee - Hoplitis claviventris
A smallish mason bee closely resembling an Osmia species.

Unless identified by a recognised expert, a photo is required. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed.
The species has been recorded from a wide range of habitats, including, for example, open broad-leaved woodland, heathland edge, chalk grassland and the coast.
Univoltine; late May to late August (rarely September).
Many nests of this bee have been found in dead stems, where the females had excavated the pith to form nesting burrows. Such stems included bramble, rose and ragwort.
Widely distributed but usually uncommon throughout much of southern England and in south Wales (where it is largely coastal); much more sporadic in the Midlands, East Anglia and northern England.
Status in Leicestershire and Rutland not known.
Leicestershire & Rutland Map
Enter a town or village to see local records
MAP KEY:
Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015