1	Fore femur incrassate in females (ratio length/width 3.4–3.5) and males (ratio length/width 3.2–3.7) (Figs 2, 4), pleurotergal spines laterally directed (Fig. 2), dark preapical wing band (width 18–20% of wing length) as broad as central band and equal in colour (Figs 9–11), abdomen club-shaped (ratio length/broadest width ≤ 3) (Fig. 8), tergites glossy, ratio length sternites 1+2+3/width posterior sternite 2 2.8–3.1, posterior arm of phallapodeme longer than anterior arm (ratio ~ 1.05–1.40) (Fig. 21)	2 (Madagopsinaapollo species group)
–	Fore femur moderately incrassate to slender in females (ratio length/width 4.6–6.0) and males (ratio length/width 4.6–6.3), pleurotergal spines posterolaterally directed, dark preapical wing band (width 13–14% of wing length) distinctly narrower than central band and darker (Figs 12–14), abdomen slender (ratio length/broadest width ~ 4), tergites thinly pollinose with a pair of pollinose lateral spots on tergite 3, ratio length sternites 1+2+3/width posterior sternite 2 4.1–4.8, posterior arm of phallapodeme shorter than anterior arm (ratio ~ 0.71–0.93)	4 (Madagopsinaapographica species group)
2	Large – females on average 9.6 mm (range 8.3–10.2), males on average 9.5 mm (range 8.0–10.1), inner vertical seta 0.8 × stalk diameter, small apical seta (23% of length of scutellar spine), male sternite 5 without combs, apophysis of surstylus short (~ 30% of length of surstylus) and bulbous (Fig. 23), subanal plate heart-shaped with bulbous lateral areas	Madagopsina apollo
–	Medium-sized – females on average 6.1 mm (range 5.4–6.8), males on average 6.3 mm (range 5.6–7.0) or just larger to 7.3 mm (M.makayensis Feijen, Feijen & Feijen, sp. nov.), inner vertical seta 1.6–1.7 × stalk diameter (Figs 1, 3), medium-sized apical seta (37–43% of length of scutellar spine) (Fig. 2, 7), male sternite 5 with or without posterior combs of spine-like setulae, apophysis of surstylus long (> 55% of length of surstylus) and slender (Figs 24, 25), subanal plate triangular (not yet known for M.makayensis Feijen, Feijen & Feijen, sp. nov.)	3
3	Body length of male 7.3 mm, apical seta 45% of length of scutellar spine, anterior central hyaline wing spot in cell r2+3 and not extending into cell r1 (Fig. 10), fore femora with ~ 48 tubercles, male sternite 5 without combs, surstylus and its apophysis both apically broadening and rounded (Fig. 24)	Madagopsinamakayensis Feijen, Feijen & Feijen, sp. nov.
–	Body length males on average 6.3 mm (range 5.6–7.0), apical seta on average 37% of length of scutellar spine, anterior central hyaline wing spot in cells r1 and r2+3 (Fig. 11), fore femora with ~ 36 tubercles, male sternite 5 with posterior combs of spine-like setulae, surstylus and its apophysis both straight, slender and not apically broadening (Fig. 25)	Madagopsina parvapollina
4	Inner vertical seta 2.3 × stalk diameter, femur 1 moderately incrassate in females and males (ratio length/width in both sexes 4.6), ratio scutellar spine/scutellum 2.1–2.3, dark preapical wing band rather vague but slightly darker than central band (Fig. 14), basal wing band extending through cell br (Fig. 14), cell br with microtrichia on apical half, tergite 3 with a pair of tiny posterolateral pollinose spots, surstylus strongly curved (Fig. 28)	Madagopsina tschirnhausi
–	Inner vertical seta 1.1–1.4 × stalk diameter, femur 1 slender in females (ratio length/width 5.3–5.9) and males (ratio length/width 5.3–6.3), ratio scutellar spine/scutellum 2.5–3.1, dark preapical wing band distinct and much darker than central band (Figs 12, 13), basal wing band not extending anteriorly of vein M1 (Figs 12, 13), cell br with microtrichia only on apical 10%, tergite 3 with laterally a pair of large pollinose spots, surstylus straight (Figs 26, 27)	5
5	Inner vertical seta 1.4 × stalk diameter, femur 1 slender in females and males (ratio length/width 5.3), ratio scutellar spine/scutellum 2.9–3.1, preapical dark band uniformly dark, only paler in cell r1 (Fig. 12), pollinose spots on tergite 3 posterolaterally located, ♀ sternite 8 divided in two sclerites, apophysis of surstylus less than half the size of central surstylus (Fig. 26)	Madagopsina apographica
–	Inner vertical seta 1.1× diameter of stalk, femur 1 very slender in females (ratio length/width 6.0) and males (ratio length/width 6.3), ratio scutellar spine/scutellum 2.5, preapical dark band with distinctly darker spot around vein R4+5 (Fig. 13), pollinose spots on tergite 3 mediolaterally located, ♀ sternite 8 a single sclerite, apophysis of surstylus equal in size to central surstylus (Fig. 27)	Madagopsina freidbergi