Based on some dictionary browsing:

mellifera means honey-bearing as in secreting a sweet nectar by flowers;

mellifica is honey-producing, that is, manufacturing honey from the
flowers' sweet nectar, for instance, by bees.

Gene Newcomb

wrote:

Could some one point out the difference on Mellifera and Mellifica.

It seems that the flora (plants) are Mellifera, while the insect is
Mellifica.

Best wishes from Mallorca, Spain

Jose Matas