Macrostomus megatarsus species-group

This group of species is characterized by male and female specimens with dark wings with distinct fenestrate hyaline spots (Figs 1B, 2B, 3B, 4B); veins R 2+3 and R 4+5 curved, converging to each other, leaving cell r 2+3 narrowed subapically; crossvein r-m placed near base of cell dm. Male tergite 8 distally with short bifid projection (Fig. 1C) or rounded (Fig. 3C). Female. Legs with mid femur, hind femur and hind tibia with dorsal and ventral pennate scales (Fig. 4A); tergite 8 (Figs 2C, 4C) slightly concave basally and deeply concave apically. Sternite 8 widened (Fig. 2D, E), laterally with oblique median sinus with a small sclerite or somewhat narrowed at distal half without lateral sinus (Fig. 4D, E). Genital fork (Figs 2D, 4D) Y-shaped, thin with elongated lateral arms. Spermatheca (Figs 2F, 4F) spherical.

Key to species of the Macrostomus megatarsus species-group

1 Wing with hyaline spots comparatively smaller (Figs 1B, 2B); cell r 1 without hyaline spot at level of cell dm spot (Figs 1B, 2B). Male fore tarsomere 1 slightly thickened. Tergite 8 with bifid projection distally (Fig. 1C). Posterior cercus elbowed and shortly inward projected (Fig. 1E, G). Hypandrium widened distally (Fig. 1I). Female: sternite 8 widened (Fig. 2D, E), laterally with oblique median sinus with small sclerite; genital fork (Fig. 2D) Y-shaped, with lateral arms longer than basal arm and somewhat inward curved...................................................................... M. megatarsus sp. nov.

- Wing with hyaline spots comparatively larger (Figs 3B, 4B); cell r 1 with small hyaline spot at level of cell dm spot (Figs 3B, 4B). Male fore tarsomere 1 not thickened. Tergite 8 rounded distally (Fig. 3C). Posterior cercus thin, upward directed (Fig. 3E, G). Hypandrium thin distally, with a distinct median acute process (Fig. 3H). Female: sternite 8 somewhat narrowed at distal half, without lateral sinus (Fig. 4E, D); genital fork (Fig. 4D) Y-shaped, with lateral arms slightly shorter than basal arm and somewhat straight....................................................................... M. polleti sp. nov.