This color system for marking and identifying queen honeybees is accepted and recognized internationally by beekeepers: White (or gray) is used for years ending in 1 or 6. Yellow is used for years ending in 2 or 7. Red is used for years ending in 3 or 8. Green is used for years ending in 4 or 9. Blue is used for years ending in 5 or 0. I have coined a little phrase that I find useful to help recall the sequence of years and colors: What Year is on the Royal Girl's Back? for White, Yellow, Red, Green, Blue. Does anyone have a Yellow or Red marked queen still working anywhere?