Actually, it's not so rare, the African Skimmer, but indeed, if seen fishing "skimming" quite spectacular. And the young ones are easily overseen: no bright colours.
Looks indeed like Periphoba arcaei L3 according to Rudolf E. J. Lampe: Saturniidae of the World Pfauenspinner der Welt.
Their Life Stages from the Eggs to the Adults Ihre Entwicklungsstadien vom Ei zum Falter. ISBN-13: 9783899370843
Thanks to Christine Young!
Their Life Stages from the Eggs to the Adults Ihre Entwicklungsstadien vom Ei zum Falter. ISBN-13: 9783899370843
Thanks to Christine Young!