Leafcutter bees are midsummer bees. They are solitary bees and nest in holes in walls, wood, etc. This male Megachile willughbiella was hanging around in my bee house six weeks ago, waiting for the females to emerge. His hairy front legs remind me of a shire horse.
Despite looking carefully in Stephen Falk's book I find female leafcutter bees difficult to identify. This one might be Megachile versicolor as it has a two-tone scopa (pollen brush) under its abdomen.
This one could be Megachile centuncularis and has a good load of bright yellow pollen. The photo shows its powerful mandibles used for cutting leaves.
I am not at all sure about this one. It was difficult to photograph as it was head down in the flowers all the time.
This one is collecting blue-grey pollen from rosebay willowherb.
There have been female leafcutters in the garden but I haven't found where they chose to nest - it wasn't in my bee house. Two photos I am very keen to take are of a bee cutting a leaf and one returning to the nest with a leaf. I have found evidence of them cutting the raspberry leaves but never caught them at it.
To see Ed Phillips' astonishing photo of a leafcutter carrying a piece of leaf click here.