Leafcutter Bee Nesting

This unidentified leafcutter bee species seems to be highly efficient in nest construction, as over 6 nests have been completed within the last 3 weeks. (Compared to another nesting species, M. pugnata, that has been constructing for 3 weeks, and still has not completed a nest.) Each cavity within the nesting box will contain approximately 6 cells with a single egg laid within each cell. This particular bee was observed collecting pollen & nectar, to provision the cells, from nearby Echinacea & Great Blue Lobelia. She then would cut near perfect circles from Hollyhock petals and Wild Rose leaves to seal each cell.