Shiny, with largely (greenish-) bronze colouration and some coppery-gold, elytra with three costae of which two are quite sharply defined; ventral side with dense mid-length silvery hairs.

Melobasis ordinata extends into the south-eastern-most part of SA. The first known record there is a single adult collected in September 2005 from Honans Scrub Native Forest Reserve near Glencoe by Bryan Haywood. Bryan also discovered the first SA breeding records in August 2021 near Moorak, SW of Mt Gambier.

In September 2023, A.M.P. Stolarski and I collected a single adult on the western side of the Mt Lofty Ranges, a remarkable outlier and extension of its known range. A second specimen that I collected there in October 2025 suggests a local breeding population rather than a vagrant occurrence from a freak long distance dispersal event.

The taxon was previously treated on this website as Melobasis sp. Hirsute prior to its publication as a new species by Levey 2023.

Blackwood Wattle (Acacia melanoxylon) and Golden Wattle (A. pycnantha) are the only adult hosts recorded in SA. In eastern States, adults have been recorded from several other Acacia species (Levey 2023), including the following which are native or established (*) in SA also: *Acacia dealbata, A. longifolia (both ssp. longifolia and ssp. sophorae), and A. suaveolens.

The SA breeding record is based on larvae and non-emerged adults found inside stems of Black Wattle (Acacia mearnsii). Three other Acacia species are reported as larval hosts interstate by Levey 2023, including A. dealbata and A. longifolia.