Key to species of Collessiama Lambkin gen. nov.

1 Wing with bright orange infuscation basally, medially, and apically, with two black infuscate bands in both males and females (Figs 1, 5–7, 16). Scutellum orange, with velvet matte reddish-black pubescence dorsally (Figs 5, 16). Abdomen bicolored (more distinctly in male), segments 1–3 orange, 4–6 (and 7 in males) reddish-brown to black (Figs 5, 9, 16–17). Male gonocoxae with distinct triangular flattened ventral flange narrowing to acute point (Figs 19, 23). Distiphallus short, broad, narrowing apically to broad ventrally-directed lobe with rows of small setiferous teeth (Figs 26–28)............................................................................................... Collessiama narelleae Lambkin sp. nov.

- Wing with orange infuscation basally (both males and females) and apically (males less distinct), two black infuscate bands, medially hyaline (Figs 29–30, 32, 38). Scutellum dark reddish brown to black, with velvet matte black pubescence dorsally. Abdomen dark, not bicolored. Male gonocoxae with distinct pointed ventral flange narrowing to acute point (Fig. 42). Distiphallus short, broad, apically forming two narrow lobes that curve ventrally, laterally with broad flanges covered with rows of small setiferous teeth, narrow ventrally-directed lobe forming distinct beak ventrally (Figs 44–46)............................................................................................ Collessiama damani Lambkin sp. nov.