I think there is some confusion going on here.  I believe the tags
referred to must be read visually.  I used to get them in the U.S. via
Norm Gary.  The tags are either color coded, or color coded with a
number.  Norm's version was metal.  Mark the bees in the field by puttng
a drop of glue on the thorax (while the bees were busy taking on fuel at
a feeder).  Put a row of giant magnets on the hive entrance and you got
about 80% of the tags back.  Others simply sit by the hive and record
colors, numbers, etc.
 
The bar code gizmo was developed at the Carl Hayden lab in Tucson.  They
even got awards for the thing.  Problem was, you can't get the bees to
run past the scanner in a way that it can reliably record the information
-  bee goes by too fast, wrong orientation, sneaks in the back door, etc.
 
Jerry Bromenshenk
The University of Montana
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