Female macropterous. Body and legs brown; antennal segment III yellow in basal half or two-thirds but brown distally, IV–IX brown; forewing brown at extreme base but clavus largely pale, with long median brown area and two clear transverse bands; distal transverse band almost parallel-sided with pale costal vein.
Head with postocular region as long as eye length; distal maxillary palp segment subdivided. Antennae 9-segmented, III–IV with sensorium curving at or around apex, extending to basal half or basal third of segment, without internal markings. Mesonotum with 3 or 4 pairs of accessory setae medially. Metanotum reticulate, with internal dot-like markings. Abdominal tergite I with faint transverse lines laterally; trichobothria on X no larger than base of major setae on X. Sternites with 4 pairs of marginal setae and 6 to 8 pairs of discal setae laterally but usually none medially; VII with 2 pairs of accessory setae scarcely distinguished from marginal setae (thus apparently 6 pairs of marginal setae).
Male similar to female but smaller. Abdominal tergite I with two longitudinal ridges. Sternites with discal setae, at least laterally; VIII–IX with each about 20 discal setae.
The genus Desmothrips is known only from Australia, with 18 described species (Pereyra & Mound, 2010). D. australis appears to be the most common member of a species complex in the South of the continent. It is distinguished because antennal segment III is extensively shaded brown in the apical third although clear yellow basally.
Known only from Australia
This species is widely distributed across southern Australia, from the south west of Western Australia to southeastern Queensland.
Collected from the flowers of many different plants, with no obvious specificity.
Adults of both sexes have been found, often with larvae, in various flowers.