[4] The forewing maculation is usually of a yellow colour, but often exhibits a distinctively red or orange postmedial (outer) area.

The male genitalia are rather unique among Pyraustinae and Crambidae in general in having the costa detached from the valva and projecting freely in a dorsal direction, with the apex bearing a field of setae.

The signum, a sclerotised structure in the corpus bursae, varies in shape among the members of Portentomorphini: a four-armed star in Hyalobathra and Cryptosara, an elongate ovoid sclerite in Portentomorpha, or two large, opposing granulose areas in Pioneabathra and Isocentris filalis.

[1] The caterpillars of Portentomorphini primarily feed on plants of the Phyllanthaceae family: Portentomorpha xanthialis feeds on Margaritaria nobilis, species of Hyalobathra are reported from Glochidion and Phyllanthus, Pioneabathra olesialis and Isocentris filalis from Flueggea, and Mabra eryxalis from Phyllanthus urinaria.

A 2019 study eventually investigated the relationships among Pyraustinae and the related Spilomelinae and found Portentomorpha together with Cryptosara and Hyalobathra to form a monophyletic group, consequently reinstating the name Portentomorphini on the level of a tribe.