Nests of Osmia uncinata. 26–27) Nest entrances sealed with leaf pulp. 28) Dissected nest with three brood cells each containing a cocoon. 29) Dissected unfinished nest with cocoon in uppermost cell and dead larva on food provision in two cells. 30) X-rayed nest with six cells containing four overwintering females, one overwintering male (outermost cell) and a dead larva on food provision.