Mario Proserpio was born on 18 March 1921 in Chatillon (AO).

After completing high school studies and obtaining a diploma from the teacher training college, he enlisted in the Regia Aeronautica. Enlisted on 20 January 1939, he attended courses at the Cameri School and obtained his pilot's licence for a Breda Ba.25 aircraft on 11 June 1939, followed by a military licence for the Ro.41 aircraft at the Castiglione del Lago School (PG) on 2 August 1939.

With the rank of Sottotenente, on 18 March 1940, he was transferred to AOI with the 413^a Squadriglia under Capitano. Corrado Santoro on the steamer ”Cristoforo Colombo” and landed in Massáua on 26 March. He arrived to reinforce the 412^a Squadriglia already in July.

A section of four CR.42s consisting of Capitano Raffi, Sergente Ottavio Bracci, Sergente Proserpio and a fourth pilot (possibly Tenente Silvio Dal Colle) moved to Tessenéi on 3 July 1940 to provide air support on the Cássala front.

Early in the morning on 4 November, three Gladiators from 1 SAAF Squadron flown by Captain Brian Boyle (Gladiator N5852), Lieutenant Leonard le Clues Theron and Lieutenant Andrew Duncan were in the air for an interdiction and surveillance cruise around Metémma, just as a formation of four CR.42s was patrolling the same area.
At 07:30, the Italians sighted the Gladiators and attacked them from higher altitude. A manoeuvred battle ensued, at the end of which the Italians claimed a Gladiator shot down as a shared between Sottotenente Proserpio and Tenente Niso Provinciali.
Allied documents do not confirm this victory and all Gladiators, in fact, return to base, although it appears that Lieutenant Theron did not participate in operations on the following days.
The South Africans, in their turn, claimed two CR.42s shot down. One was claimed by Lieutenant Theron, who reported seeing the enemy pilot descend by parachute, while the second was claimed by Captain Boyle. Lieutenant Duncan claimed a third CR.42 but this was unconfirmed.
It seems that Lieutenant Theron’s claim was Sottotenente Proserpio who was hit in the left shoulder by a bullet that fractured his collarbone and lacerated his scalp at the nape of his neck, a blow that forced him to bale out, but he managed to land safely and then walk back to his lines.
Italian sources also state that all other CR.42s were damaged, but still manage to return to base.
Sottotenente Proserpio, who had just turned 19, was awarded the Medaglia d’argento al valor militare and was repatriated after convalescence.

Proserpio went ashore in enemy territory but was promptly spotted by our soldiers and rescued. Repatriated on 29 January 1941, he spent two months at the Rizzoli Hospital in Bologna to treat wounds to his left shoulder. The convalescence period is also spent in the mountains in the snows of Cortina (BL).

On 3 June 1941, Proserpio was posted to the 4^o Stormo based in Gorizia, but on 23 July 1941 he returned to the 153^o Gruppo Autonomo with the 374^a Squadriglia, just when the Macchi C.200s of this unit were transferred to Libya.

On 30 October 1941, during an interception mission over Benghazi, two Martin Maryland Mk.II bombers of 21 SAAF that he was pursuing collided. Proserpio followed the forced landing manoeuvre of one of the two (aircraft No. 1672/B), without firing a shot at the already vanquished enemy. The South African crew of four aviators is taken prisoner.

On 13 January 1942, Proserpio was repatriated, also to undergo medical treatment. After recovering, he was promoted to SPE for war merits and on 27 June 1942 he was back at Caselle (TO) with the 153^o Gruppo, now no longer autonomous but part of the 53^o Stormo.
The unit carried out surveillance missions in the skies over Turin and Milan. In August, the Gruppoi was equipped with the new Macchi C.202. With this aircraft, the unit was engaged in Mediterranean operations against Malta for about three months, from October 1942 to January 1943, carrying out free-flying missions and protection of naval and air convoys.

On 6 January 1943, during a wartime flight to protect King Victor Emmanuel III's plane as it passed through the main airports involved in the offensive against Malta, Proserpio's C.202 had a mechanical failure.
Promptly informing the base of the problem on board, and despite the advice to abandon the aircraft, in a attempt to save the plane Proserpio tried to make an emergency landing near Catania, in Giarre Riposto. Unfortunately, the manoeuvre failed and the plane collided with one of the many dry stone walls dotting the countryside in the area. Radio transmissions stopped abruptly at that moment and Proserpio died of his injuries in the crash.

At the time of his death, Proserpio was credited with 1 shared biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
	04/10/40	07:20-08:15	1	Gladiator	Probably destroyed	Fiat CR.42		Gallàbat front	412a Squadriglia
	04/11/40	07:30	1	Gladiator	Shared destroyed	Fiat CR.42		Metémma area	412a Squadriglia

Biplane victories: 1 shared destroyed, 1 probably destroyed.
TOTAL: 1 shared destroyed, 1 probably destroyed.
(a) Claimed in combat with Gladiators from 1 SAAF Squadron, which claimed 3 CR.42s (1 unconfirmed) without losses. The 412^a Squadriglia claimed 1 Gladiator while losing 1 CR42.

Sources:
Dust Clouds in the Middle East - Christopher Shores, 1996 Grub Street, London, ISBN 1-898697-37-X
I Cavalieri Erranti - Ludovico Slongo, Stefan Lazzaro, Eugenio Eusebi, Michele Palermo and Danilo Ventura, 2023, ISBN 978-88-87952-37-7
Springbok Fighter Victory: East Africa Volume 1 1940 – 1941 - Michael Shoeman, 2002 African Aviation Series No. 11, Freeworld Publications CC, ISBN 0-958-4388-5-4
Additional info kindly provided by Stefano Lazzaro and Ludovico Slongo.