Syntonarcha iriastis

{{Short description|Species of moth}}

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| taxon = Syntonarcha iriastis

| authority = Meyrick, 1890

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Syntonarcha iriastis is a moth in the family Crambidae. It was described by Edward Meyrick in 1890.{{cite web |last=Nuss |first=M. |display-authors=etal |date=2003–2017 |url=http://globiz.pyraloidea.org/Pages/Reports/TaxonReport.aspx |title=GlobIZ search |website=Global Information System on Pyraloidea |accessdate=January 15, 2018}} It is found in the western Pacific, including Hong Kong, New Caledonia and most of Australia, where it has been recorded from Western Australia, the Northern Territory, Queensland and New South Wales.[http://lepidoptera.butterflyhouse.com.au/odon/iriastis.html Lepidoptera Larvae of Australia]

Males of the species produce an ultrasonic sound by rubbing their genitalia against one of their sternites. It is hypothesized that this is used to attract mates over long distances.{{cite journal |last1=Gwynne |first1=Darryl T. |last2=Edwards |first2=E.D. |date=December 1986 |title=Ultrasound production by genital stridulation in Syntonarcha iriastis (Lepidoptera: Pyralidae): long-distance signalling by male moths? |journal=Zoological Journal of the Linnean Society |volume=88 |issue=4 |pages=363–376 |doi=10.1111/j.1096-3642.1986.tb02253.x}}

The wingspan is about 25 mm. The forewings are light brownish ochreous. The hindwings are whitish.[https://archive.org/stream/proceedingsoflin0204linn#page/1107/mode/1up Proceedings of the Linnean Society of New South Wales. (2) 4 (4): 1107]