Key to the Neotropical species of Austrohelea

1 Males............................................................................................... 2

- Females............................................................................................. 4

2 Wing membrane mostly pale, lightly infuscated between costa-radius and radius-medius (Fig. 23); hind tibia with 3 large subapical spines (Fig. 22); aedeagus heavily sclerotized with broad, long basal arms with rounded apices (Figs. 24, 34); basal apodemes of parameres very broad with shallow obtuse angle between anterior, posterior arms (Figs. 24, 33)... A. spinosa n. sp.

- Wing mostly or entirely infuscated; hind tibia without large subapical spines; aedeagus lightly or heavily sclerotized with relatively short basal arms with blunt apices; basal apodemes of parameres slender to moderately broad with deep acute angle between anterior, posterior arms.......................................................................... 3

3 Wing membrane uniformly lightly infuscated (Fig. 14); aedeagus with very shallow basal arch, basal arms slender slightly curved, distal portion lightly sclerotized with rounded apex (Figs. 15, 32); basal apodemes of parameres slender, anterior arm twice as long as posterior arm (Figs. 15, 31)...................................................... A. sirii n. sp.

- Wing membrane mostly darkly infuscated (Fig. 3); aedeagus with deep triangular basal arch, basal arms broad greatly recurved with blunt apices, distal portion heavily sclerotized (Figs. 4, 30); basal apodemes of parameres with broad posterior arm that is twice as long as anterior arm (Figs. 4, 29).......................................... A. shannoni (Wirth & Blanton)

4 Small species (wing length 1.16 mm); wing membrane darkly infuscated with dense, coarse macrotrichia (Fig. 18); palpal segment 3 with large apical sensory pit (Fig. 17); spermathecae pyriform, unequal, with short, broad, truncate necks (Fig. 19)............................................................................................. A. sirii n. sp.

- Large species (wing length 1.57‾ 1.85 mm); wing membrane darkly or lightly infuscated with sparse to moderately dense thin macrotrichia; palpal segment 3 without sensory pit; spermathecae ovoid, subequal.................................. 5

5 Hind femur greatly swollen; spermathecae with short broad necks (Fig. 28)........................... A. spinosa n. sp.

- Hind femur slightly swollen (Fig. 6); spermathecae with moderately long slender necks (Fig. 12)................................................................................................... A. shannoni (Wirth & Blanton)