Sexual dimorphism of broad-horned flour beetle (<i>Gnatocerus cornutus</i>).

a) male, b) female, top, frontal view; middle, dorsal view; bottom (inset), dorsal view of magnified mandibles. Lateral region of male head (gena, ge) is enlarged, and two head horns (hh) are located between eyes (top and middle panels). Females lack mandibular horn, head horn, and lateral protrusion of gena (b, top to bottom panels).