At the left hand a snapshot of the so-on_hive, populated with Buckfast bees. At the right hand, a snapshot of the okno_hive, populated with European Black bees.

The Buckfast bee is popular among beekeepers and is available from bee breeders in several parts of the world. Most of their qualities are very favorable. They are extremely gentle. Their main drawback is that they are very liberal in their application of propolis to inner surfaces of their hives, thus acting to defeat one of the main purposes of the modern beehive — that combs should be easily removable for inspection.
The European dark bee can be distinguished from other subspecies by their stocky body, abundant thoracal and sparse abdominal hair which is brown, and overall dark coloration; in nigra, there is also heavy dark pigmentation of the wings. Overall, when viewed from a distance, they should appear blackish, or in mellifera, rich dark brown. For breeding pure dark bees according to the standard, details of the wing veins are nowadays considered to be the only reliable distinguishing character.

http://en.wikipedia.org/wiki/Buckfast_bee
http://en.wikipedia.org/wiki/European_dark_bee