Female macroptera. Body pale yellow, antecostal ridges on tergites III–VIII weakly shaded, sternites III–VII with no shading; fore wings pale; antennal segments III–IV with apex shaded, V–VIII uniformly dark. Antennae 8-segmented. Head with vertex closely striate, ocellar triangle with weak reticulate pattern; ocellar setae pair III on anterior margins of triangle; 4 pairs of post-ocular setae. Pronotum with transverse striae irregular; 4 pairs of posteromarginal setae, S2 about twice as long as S1. Metanotum with transverse striae, median setae behind margin. Fore wing clavus with 4 marginal setae; first vein setae 3–4+4–8+1+1+1; second vein 3–5 setae; posteromarginal fringe cilia wavy. Tergites I–VI median setae small and wide apart; tergal microtrichial fields with 3 discal setae; VII with posteromarginal comb extending toward mid line; VIII with posteromarginal comb complete, no discal microtrichia medially; tergite IX without discal microtrichia. Sternites with lateral microtrichial fields weak, not extending mesad of marginal setae S2.
Male macroptera. Similar in colour and sculpture to female, but smaller; abdominal segment IX without drepanae.
The genus Scirtothrips comprises over 100 described species worldwide, with 21 species known from Australia most of which are endemics to this continent. These species all have the lateral thirds of the abdominal tergites covered in closely spaced rows of fine microtrichia, and in many species the sternites also bear similar microtrichia. The antennae are 8-segmented, except inS. casuarinae and S. solus, both forewing veins have an irregular and incomplete setal row, and a median spinula is present on both the meso and metafurca. S. helenae has transverse sculpture on the metanotum, unlike any other member of the genus, and the median tergal setae are wide apart.
Known only from Australia.
South Australia, New South Wales.
Feeding and breeding on young leaves surrounding the flowers.
Brachychiton populneus (Sterculiaceae). .
Scirtothrips helenae Palmer & Mound
Hoddle MS & Mound LA. 2003. The genus Scirtothrips in Australia (Insecta, Thysanoptera, Thripidae). Zootaxa 268: 1-40. http://www.mapress.com/zootaxa/2003f/zt00268.pdf