Updated key to Myaptex group of genera

(only last couplets (8–10) modified from Soares et al. (2025)

8 Mystax composed of few sparse macrosetae mostly restricted to lower facial margin (fig. 16C–D in Soares et al. (2025)); at least one pair of well-developed anterior dorsocentral macrosetae (fig. 16A, D in Soares et al. (2025)); vein R 4 ending at wing apex (fig. 393 in Papavero et al. (2009)); phallus ending in one prong; three coiled spermathecae (figs 398, 402 in Papavero et al. (2009)) (Chile)................................................................ Rhadinosoma Artigas, 1970

- Mystax composed of abundant and dense macrosetae not restricted to lower facial margin (Fig. 1C, D; fig. 1 in Vieira et al. (2014); fig. 17C–E in Soares et al. (2025)); anterior dorsocentral macrosetae absent (Fig. 1A; fig. 1 in Vieira et al. (2014); fig. 17A in Soares et al. (2025)); vein R 4 ending before wing apex (Fig. 1E; fig. 19 in Vieira et al. (2014); fig. 17B in Soares et al. (2025)); phallus ending in two or three prongs; two or three oval spermathecae (figs 410, 413, 422 in Papavero et al. (2009); fig. 28 in Vieira et al. (2014))............................................................................ 9

9 Frons with parallel edges dorsally in anterior view (fig. 17D, E in Soares et al. (2025)); fore and mid femora with uniform white long macrosetae and setae (fig. 17A in Soares et al. (2025)); phallus with two prongs and female with two oval spermathecae (figs 410, 413 in Papavero et al. (2009)) (Mexico).................................... Scarbroughia Papavero, 2009

- Frons with convergent edges dorsally in anterior view (Fig. 1C); fore and mid femora without uniform white long macrosetae and setae (Fig. 1A); phallus with three prongs (Fig. 1G, H) and female with three oval spermathecae (Fig. 3F; figs 6, 28 in Vieira et al. (2014))........................................................................................ 10

10 Postpedicel lanceolate (Fig. 1C, D); posterior margin of sternite 8 simple and straight, without projections (Figs 2J, 5I, 7I); epandrium wide in lateral view (Fig. 2B, D); gonocoxite mostly subtriangular in lateral view (Figs 2F, 11F, 14F); gonostylus more or less straight with base hidden behind gonocoxite in lateral view (Figs 2E, K, 5E, 11E, J); phallus unconcealed, ending in three long prongs (Fig. 2G); female tergite 8 only 1.5 times length of tergite 7 (Fig. 3B, C, E); female sternite 8 with setae basally (Fig. 3B, D, E) (Trinidad and Tobago, Venezuela and Brazil).............................. Merucata gen. nov.

- Postpedicel oval (figs 1, 17, 26, 29 in Vieira et al. (2014)); posterior margin of sternite 8 with projections or strongly bulged and pronounced at posterior margin (figs 24, 36 in Vieira et al. (2014)); epandrium more or less elongate and subrectangular in lateral view (figs 3, 20, 32 in Vieira et al. (2014)); gonocoxite more or less slender, tapering towards a rod-like rounded apex; gonostylus arched and visible from its base in lateral view (figs 4, 25, 34 in Vieira et al. (2014)); phallus concealed ending in three short prongs (figs 6, 23, 35 in Vieira et al. (2014)); female tergite 8 more than 2 times length of tergite 7; female sternite 8 bare (figs 26, 28 in Vieira et al. (2014)); (Mexico and Costa Rica).......................... Martintella Artigas, 1996