According to Roger Morse, the correct form is "honey bee."
 
Like bumble bee, sweat bee, carpenter bee, etc.
 
Some other names are correct all in one:
 
dragonfly
housefly
butterfly
 
Honeybee, honey bee, hon eybee -- still we are talking about the same thing.
There is no law requiring strict adherence, but the major entomological
societies have settled on the "official" form, "honey bee" as the common
name for Apis mellifera.