Key to the known species of Apterobiroina L. Papp, 1979

1. Haltere completely absent; ocellar seta very large. Thorax and legs all black. Dorsal seta on female epiproct short (Fig. 18) A. truncata sp. n.

– Haltere normal, though small; ocellar seta smaller. At least tarsi, bases and apexes of tibiae yellow. Dorsal seta of female epiproct long (Fig. 16) 2

2. All parts of head, incl. antenna, yellow; all parts of legs but fore tibia yellow. Fore tibia brown. Knob of haltere wax-yellow to ochre, stalk even lighter. Apical row of pegs on ventro-medial process of synsternite with 16 pegs (Figs 9–10). Distiphallus long (Figs 12–13). Surstylus smaller, in 2 smaller lobes (Figs 14–15) A. flavipes sp. n.

– Only anterior 1/3 to 2/5 of frons yellow; and only tarsi, bases and apexes of tibiae reddish yellow. Haltere with black knob and brown stalk. Apical row of pegs on ventro-medial process of systernite with 12 pegs. Distiphallus short (Figs 5–6). Surstylus larger, in 2 distinctly divided lobes (Fig. 4) A. australis L. Papp, 1979