Female macroptera. Body yellow with faint brown shadings on vertex, pronotum and terminal antenna segments; tergites III–VIII with antecostal ridges weakly shaded; fore wings uniformly pale. Antennae 8-segmented. Head with postocular region very short, occipital carina almost confluent with posterior margin of eyes; mouth cone extending across mesosternum; ocellar setae pair III closer together than their length, arising between anterior margins of posterior ocelli; one pair of post-ocular. Pronotum with faint transverse striae widely separated; 4 pairs of short posteromarginal setae. Metanotal reticulation elongate, median setae close to margin. Fore wing clavus with 4 marginal setae; second vein with 4 setae; posteromarginal fringe cilia wavy. Tergites II–VI median setae closer together than their length; tergal microtrichial fields weak, with 3–4 discal setae; VIII with no discal microtrichia, posterior margin concave with complete comb; tergite IX with no discal microtrichia. Sternites with lateral microtrichial fields weak, scarcely extending mesad of marginal setae S3, apparently absent on sternite VII.
Male macroptera. Similar to female, but mouth cone shorter and vertex longer; tergite IX with pair of curved drepanae; aedeagus without an array of spines.
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 in S. 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. The mouth cone is unusually elongate in females of S. tenor, and in life it is directed posteriorly rather than ventrally as in other Scirtothrips species. The vertex of females is exceptionally short, with the posterior margin of the head almost confluent with the posterior margin of the eyes, although in males the length of the vertex is at least equal to the width of one ommatidium. The striae on the head and pronotum are weaker than in typical Scirtothrips species, the microtrichia are reduced on the anterior lines of sculpture on each tergite, and the sternal microtrichial fields scarcely extend mesad of setae S3.
Papua New Guinea, Australia.
Northern Territory; Queensland (Badu Island); Western Australia (Kununnura).
Feeding and breeding on young emerging fronds, causing visible damage.
Cycas armstrongi, C. badensis, C. pruinosa, C. revoluta (Cycadaceae).
Scirtothrips tenor (Bhatti & 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