Figures 16-25 from: Müller A, Prosi R, Taylor S, Richter H, Herrmann M, Weibel U (2020) Unique nesting biology of Osmia ( Melanosmia) uncinata, a Palaearctic osmiine bee specialized on thick-barked conifers (Hymenoptera, Megachilidae). Alpine Entomology 4: 157-171. https://doi.org/10.3897/alpento.4.53489

Figures 16-25 Nest architecture of Osmia uncinata. 16) Several years old nest after uppermost bark layer has flaked off. 17) Entrance to old nest seen from below. 18–25) Dissected nests consisting of a single burrow (18–22) or of one to three side burrows branching off the main burrow (23–25).