Leucoptera laburnella – a second generation mine on Laburnum.
Leucoptera laburnella leaf mine- 15/09/2017
Phyllonorycter harrisella – a common species on Oak.
Phyllonorycter harrisella leaf mines- 15/09/2017
Apart from rearing the adults it is easiest to confirm by finding vacated mines which still contain the old pupal cases. Look on the tips of the empty pupal case at the spines on the cremaster under a microscope as they differ from the other Oak feeding Phyllonorycters.
We are finding your leaf mine reports very useful except we don't seem to be finding any occupied mines locally. We have found a case bearer on Hawthorn which is not like previous ones we have had on Hawthorn.
Most of the Stigmella mines I find are vacated. They are only tenanted for a few days, so you need a certain amount of luck finding them tenanted.
I don't know how to separate the Coleophora cases on Hawthorn. The MOGBI key has determination uncertain for this group, yet in the NMRS guidelines Coleophora spinella is down as category C2 = A good quality photo or specimen of the case and plant/pabulum is required. I'll have to look into this.
Sent the query about your Coleophora case up to the National Verification Panel and heard back from John Langmaid “It rather depends on whether it is bivalved or trivalved and I can’t tell from the photo. I would rather assume it’s the latter in which case it is almost certainly Coleophora spinella.”
I'm still puzzled though as MOGBI mentions Coleophora coracipennella also having a trivalved case and this sometimes feeds on Hawthorn. Hopefully this will become more clear once the updated 'Emmet Field Guide' is published.