Today she looks quite different and has moved to a new leaf:
But she is still only 10mm long, unlike Agni, who changed into 4th instar today and is over 15mm.
Is this natural size variation or is she perhaps one of the few larvae that hibernate in 2nd instar (I have definitely recorded this phenomenon before). Or, was that not a skin change at all, despite appearances? If she lives long enough I should be able to answer these questions over the course of the next couple of months, I suppose. Several other very small caterpillars have adopted a similar, hunched attitude, with the same shiny, yellow shoulders. Other caterpillars are significantly bigger.