There are a fair few rare bee species, with some literally on the brink of extinction, but few more so than the Shrill Carder Bee (Bombus sylvarum).
Ashy Mining Bee
The Ashy Mining bee is just one of the 65 or so Andrena species in the UK. These are the ground nesting bees that excavate their nests in close mown areas of the lawn, bare soil and sunny banks.