Back on 10th October I collected a couple of mines from leaves of Snowberry growing in our garden and I thought that they'd turn out to be Phyllonorycter trifasciella which I've had here previously as the adult moth as well as finding mines. That species has three generations each year and adults should have emerged by now, so today I decided to open the mines to see what was inside. I was very pleased to find that both actually contained the greenish rugby ball-shaped cocoons of Phyllonorycter emberizaepenella which is bivoltine and over-winters as a pupa (trifasciella doesn't form a recognisable cocoon). There are just five previous records of emberizaepenella for Bucks so this seems to be quite a good discovery. It becomes this year's 40th micro species found only as a leaf-mine here in the garden (there have been others where I've had the adult too) so shows how useful it can be to search out this stage of the life-cycle. In this particular case I shall retain the cocoons and hope to see the adult moths emerge early next year.
Cocoon of Phyllonorycter emberizaepenella, Westcott