Key to species of the Protopolybia sedula species-group

1. Mesoscutum and scutellum with strong and dense micropunctation and shallow mesopunctation (Fig. 28); color brown, richly marked with yellow to whitish spots (Figs. 10 and 12), metanotum triangular, metanotal process elongate (Fig. 11); pronotal fovea distinct, preceded by anterior prominence relatively distant from the pronotal carina (Fig. 21)....................................................................................................... P. weyrauchi Bequaert

- Mesoscutum and scutellum with moderate micropunctation and shallow mesopunctation (Fig. 25–27); scutellum with more sparse mesopunctation; color variable, not brown; metanotal process not elongate (Fig. 1 and 4); anterior prominence in front of the pronotal fovea extending above and close to pronotal carina, nearly collinear with fovea (Fig. 22–24).............. 2

2. Pronotal carina weakly lamellate, little extended below (Fig. 23); petiole of T1 narrow, without wing-like processes; species almost entirely black (form dark) or black moderately marked with yellow spots (form sedula) (Fig. 7 and 9); front with two small yellow spots (Fig. 8)................................................... Protopolybia sedula (de Saussure)

- Pronotal carina blunt, non-lamellate, distinctly extending downwards at side (Fig. 22 and 24); petiole of T1 reduced, wing-like processes not very sharp (Fig. 3).......................................................................... 3

3. Species yellow, with light ferruginous and very few black markings, commonly on mesoscutum; pronotal fovea distinct and deep, metanotal lobe with apex pointed (Fig.4–6)................................... Protopolybia amarella Bequaert

- Species black, richly marked with yellow spots; front with extensive Y-shaped mark (Fig. 2); pronotal fovea distinct, but shallow; metanotal lobe with apex slightly rounded (Fig. 1)........................... Protopolybia acutiscutis (Cameron)