Bronze to dark grey-bronze colouration and a broad, thick body shape, especially in females. Head with a shallow depression medially at the junction of the anterior frons and clypeus, a feature unique within the species-group (Levey 2023). Readily distinguishable from M. sordida by the puncta of the medial pronotum not being transversely elongated, and from M. soror soror by the rather weak elytral costae and more reduced hair cover on the sides of the pronotum and elsewhere. Males often with greenish colouration on the frons (in contrast to the reddish-copper colouration seen in M. adusta. As with M. adusta, the apical ventrite of M. rothei also has the lunate puncta coalesced, but they do not form such well-defined grooves parallel to the margin. The aedeagus of M. rothei is very distinctive, being relatively short and broad, and with its sides diverging strongly from the base to an expanded middle section.

Named by Blackburn 1888a after a Mr. Rothe of Sedan (in the MU Region against the eastern margin of the Mt Lofty Ranges) from whom he received a collection of this species.

In the protologue, Blackburn 1888a commented that "the peculiar form of the thorax distinguishes this insect from all other species that bear any resemblance to it" and drew attention to "the prosternum a little elevated across its front margin instead of being declivous". These features are difficult to interpret.

Until November 2020 Melobasis rothei was included on these pages within the entity Melobasis sp. Brown. I am grateful to Brian Levey (2020, pers. comm.) who identified the images of specimen PL3195B shown here as being M. rothei, having previously seen the type and matched specimens of this species against it.

Levey 2023 reports that adults have been collected from foliage of Senna and Acacia species. My collections in SA have all been from Senna artemisioides.