There are 25 species in Britain, but with queens looking different to males (and sometimes to workers), as well as different colour forms for most species, there can be a bewildering array of different-looking bees. When, later in the year, sun-bleached and worn bees are prevalent, identification can be very tricky indeed!
The first thing to be aware of is that only seven or eight bumblebee species are both widespread and abundant: these species are likely to make up around 95-99% of your bumblebee sightings. There are a further six species (the cuckoo bumblebees) which are parasitic in the nests of these common species and so are largely similarly widespread, but at a much lower abundance. The remaining 11 species tend to be localised or habitat-specific, and are correspondingly rarer, though they can be abundant where present.
Click on the link to read the rest of the article: Identification tips – Bumblebee Conservation Trust