Image of Melittia calabaza Duckworth & Eichlin 1973

Description:

Single individual observed feeding on African blue basil. I do not believe that I have ever seen this species before at the location. As it fed, its wings flapped rapidly, and what looked like thickly covered hind legs pulsated up and down rhythmically. I am placing it in the Sesiidae family because it has some features that are similar to those of Melittia calabaza (which I have seen at this location, but which this specimen is not). Any help on identification would be greatly appreciated.