Detail head red mason bee (osmia rufa), made with magnification factor 6 and f/14. It is a single picture made in our garden, using a Canon 7D, a Canon MP-E 65 mm f/2.9 and a Canon 2x teleconverter. The bee was alive and kicking.
Osmia rufa is a species of solitary bee, also known as the red mason bee due to its habit of using mud to build small cavities within its nest.
The species is most active during the spring and early summer although it can be seen as far as late June. Despite being classed as solitary, these bees are gregarious. The female is larger/broader than the male and has 2 large horns on the head.The female has a much smaller sting than honeybees or wasps.The male has no sting. The size is around 10 mm (source Wikipedia).