Megamelus maculipes is easily distinguished from the other South American species of the genus by the long first antennal segment, the greatly concave anal
emargination of the pygofer, the strongly excavated and bordered ventral margin of the anal segment, long anal style, left subapical process on the aedeagus, and the lobed small projection of sternite VIII, median process on the lateral gonapophysis VIII which are tongue shaped and J-shaped in lateral view.
guanacaste Dominguez, 1995) by the following combination of characters: 1) medial denticle on anteromedian
emargination of labrum much larger than others; 2) anterior tibiae slightly stained black toward the apex; 3) medial femora with few dorsal spines, similar to short thick needles; 4) hind femora with numerous dorsal spines, similar to short thick needles; 5) medial femora with no medial black markings, apical brown markings.
The 10th tergite ends with two squared apices, toothed on inner side, separated by a wide
emargination (Figs 36, 37).
Ventral rim of pygophore with the medial U-shaped
emargination relatively shallow (vre), 1 + 1 flaps slightly bending dorsad into the genital cup ([approximately equal to] Brepholoxa heidemanni Van Duzee); inferior folder of ventral rim developed in a medial bilobed projection (vrp), apparently an autapomorphy of Aleixus.
Mentum deeply emarginated at apex,
emargination Vshaped.
Tsuji (2006) scored the maxilla and the quadratojugal as being in contact in Nyctiphruretus based on illustrations of Ivakhnenko (1979) and Lee (1995, 1997), when in fact they are not due to a temporal
emargination between the quadratojugal and the jugal (Fig.
Dorsal surface: Anterior margin with shallow median
emargination (Fig.
Eyes are tan/ light-brown, large, and convex without internal
emargination.
2A); posterior margin of genital opening deeply emarginated,
emargination round, surrounding parameres (Fig.
Anterior clypeal margin strongly convex or with a central
emargination 5 3--More than 20 longitudinal rugae between frontal carinae.
Sternum: Sternum type 2 (Soleglad & Fet 2003), much wider than long; apex width equal to posterior width; posterior
emargination quite well developed, with convex lateral lobes conspicuously separated.
Pronotum with median and lateral gibbosities strongly elevated; laterobasal margin concave; basal
emargination deep (fig.
