Similar to M. splendida but differs noticeably in its more elongate shape, and the elytra often have a greater extent of maroon/purple coloration and narrower green/blue vittae.

Melobasis purpurascens appears to be an uncommon species in South Australia and restricted to areas of higher rainfall, although there is a 1936 collection labelled with the general locality of Yorke Peninsula. As with M. splendida, it can be difficult to separate from Melobasis innocua without male genitalia, and there is a possibility that specimens from the lower SE region, at least, may be that species.

A review of host plant records for M. purpurascens by Hawkeswood 2006b lists a variety of larval hosts, including the following species which also occur SA: *Acacia dealbata, *A. longifolia ssp. longifolia, A. l. ssp. sophorae, A. melanoxylon, and *Citrus spp. (cultivated). The new SA breeding record presented here was obtained from Bryan Haywood who reared two adults in billets of Myrtle Wattle Acacia myrtifolia south of Mount Gambier.

None of the other SA records include host plant details, but interstate adults have been caught on: Banksia marginata, Acacia longifolia ssp. longifolia, A. melanoxylon, Leptospermum spp. and Ozothamnus ferrugineus (Hawkeswood 2006b; Bellamy et al. 2013). All the larval and adult host records need to be considered with caution due to the difficulties with identification in this species-group.