Desoria trispinata is probably another alien, imported with horticultural materials. It looks disarmingly familiar, like a large Parisotima notabilis but with a rectangular Isotoma-like eye patch. In fact it is a recently described species, found by Arne Fjellberg in Norway, and a similar species (with a different labrum) in Germany. This species dominated the Collembola community of the Whitelands College compost heap in June 2010. Apparently the same thing (I'm awaiting DNA results, as of early 2011) was also dominant in litter in my own garden in January 2011, for the first time. It keys to Isotoma viridis group under Steve Hopkin's AIDGAP key, the giveaway being the colour (which is admittedly a poor taxonomic character) and a lack of manubrial teeth. Otherwise it's a plausible fit, and I suspect that for decades to come there will be determinations of Isotoma viridis which are in fact this species!