It belongs to the order Urostylida, but identifying to genus level will be hard, I think.
I puzzled over it, yesterday, but kept quiet because I could not be sure whether the creature has transverse cirri (aka "anal styles" or "anal cirri"). These are the cirri we often see as a small patch on the ventral surface, at the posterior of the cell, often running perpendicular to the body (or set at an angle). If they are indeed absent, as it appears, we rule out Urostyla, because it has them (lllustrated Guide vol. 1 p. 441 and NIES entry on Urostyla...although Borror (1972) allows some Urostyla to be without them).
So, we wade into the swamp of the Urostylids, considering creatures like Eschaneustyla, Hemicycliostyla and Australothrix, which are defined as lacking transverse cirri, and Pseudourostyla (frustratingly described as
usually having transverse cirri!). Looking for good descriptions and pictures of these guys, we go back to Stokes (1886) . Along the way, we learn that Hemicycliostyla and Eschaneustylas were moved to Urostyla, in Borror's revision of 1972. While Eschaneustyla still stands in the ISOP guide, Hemicycliostyla has vanished altogether.
All the while, one keenly feels the lack of a particular resource: Berger's Monograph of the Urostyloidea. And one is painfully aware that even Berger is a bit out of date...for, even as we speak, molecular/genetic research based on small subunit rRNA sequences is rewriting the family tree!
So, I give up. It is some kind of Urostylid.
