The female hedychrum niemelai wasp, which is a bright red and green metallic colour, was found by the Surrey Wildlife Trust (SWT).
It is also known as a "cuckoo wasp" as it lays eggs in the nests of other wasps, leaving them to care for them.
The SWT said its "stunning armour plating" had evolved for protection, in case it gets caught in the act.
It was found by volunteer assistant ranger, Iain Buchanan, as he helped Nuffield Science students study the silver-studded blue butterfly and two other species of wasp.
He said: "Wasps generally get a bad press; in fact the mere mention of a wasp often causes a sense of fear and loathing.
"But how could anyone not be bedazzled by the beauty and splendour of this little gem? It's a real jewel amongst wasps."
The ruby-tailed wasp is classed as a "nationally scarce" species, restricted to southern England, and has never before been found on Whitmoor Common.
Reference: BBC News Surrey
