Macchi C.205 Veltro - Italian Co-Belligerent Users

After the armistice of 8th September, there were just 50 Veltros in the south, plus other six of them flying from the centre of Italy to the south. All those 56 of them would be the backbone of the early Italian Co-Belligerent Air Force serving mainly in the 51º Stormo (51st Air Regiment).
Some of them were originally unfinished Macchi C.202 that were finished as Veltros with the available engines at the factories.
Approximately 20 of them were converted following this technique, however, it's not clear if all of them received the 20mm cannons in the wings.
During 1944 eighteen Veltros of the Serie III replaced their cowling machine guns with an additional fuel tank and received the name of Macchi C.205S.

Sources:
1. https://it.wikipedia.org/wiki/Macchi_M.C.205
2. Salamander Books - The Complete Book of Fighters