Il Neo[1] (La Mouche) is an opera in 1 act, 3 tableaux (novelletta musicale in 3 piccoli quadri — musical novelette in 3 little tableaux) by Henrique Oswald to an Italian libretto by Eduardo Filippi after a novella La mouche by Alfred de Musset.

[2] Il Neo is Oswald's second opera written some thirty years after his first (1872).

Compositions by Mascagni, Leoncavallo, Giordano, Puccini, Massenet and Wagner were staged.

[4] It was definitely performed in 1954, again by Alfredo Colosimo, this time in Minas Gerais, with Mario de Bruno conducting.

[4] A Berceuse from this opera arranged by the composer for voice and piano was published by Bevilacqua in supplement to Renascença No.