type Harmonicon rufescens F. O. Pickard-Cambridge, 1896; gender neuter

N.B.: removed from the synonymy of Diplura C. L. Koch, 1850 by Maréchal & Marty, 1998, contra Raven, 1985a, but seemingly construed to include only the type species (H. rufescens) and one new species, as no mention was made of either H. nigridorsi Mello-Leitão, 1924 or H. riveti Simon, 1903 (Pseudohermachura Mello-Leitão, 1927 and Prosharmonicon Mello-Leitão, 1938 were confirmed as junior synonyms of Diplura rather than H. by Drolshagen & Bäckstam, 2011: 91); Harmonicum is an invalid emendation.

Harmonicon audeae Maréchal & Marty, 1998: 500, f. 1A-C, 2A-B, 3A-E, 4A-C (Dmf).

Harmonicon candango Wermelinger-Moreira, Castanheira & Baptista, 2024: 266, f. 2A-J, 3A-G (Dmf).

Harmonicon cerberus Pedroso & Baptista, 2014: 79, f. 1-11 (Dm).

Harmonicon oiapoqueae Drolshagen & Bäckstam, 2011: 92, f. 1-7 (Dmf).

Harmonicon rufescens F. O. Pickard-Cambridge, 1896: 756, pl. 33, f. 3, 6, pl. 35, f. 2-3 (Dj).
Harmonicon rufescens Maréchal & Marty, 1998: 500 (Tj from Diplura).
Harmonicon rufescens Wermelinger-Moreira, Castanheira & Baptista, 2024: 264, f. 1A-G (Df).