Elytra black with scattered irregular white hair-scale patches, and these are also well developed on the pronotum. Head, pronotum and scutellum copper to gold in females, green in males.

Very similar to Diphucrania vicina from Vic., NSW and Qld. Barker 2006b noted that the male genitalia resemble those in C. vicina but described the latter as being a much smaller species which lacked setae on the pronotum. However differences in pronotal setae patches appear to break down, and the taxonomic status of D. aenigma as a separate species warrants investigation.

Adults have been collected from two species of Heath, with large numbers found on one of these, Ruddy Beard-heath Styphelia. rufa. It is suspected that species of Styphelia, Leucopogon and possibly other related genera of family Ericaceae (formerly Epacridaceae} may be larval hosts. There is some support for this with a dead larva of subfamily Agrilinae being discovered in the stem base of a S. rufa plant on which adults had previously been collected.