Possible Stigmella hybnerella leaf mine - help needed
I collected this Hawthorn leaf from the coastal path a couple of days ago. I think it looks like a vacated Stigmella hybnerella leaf mine, but I am wondering about the slender part of the gallery - it is meant to have "black linear frass with narrow clear margins" but this gallery doesn't look as clear as other examples I have seen online. Using the key I haven't found an alternative that it could be. The dark patch behind the gallery is present on other parts of the whole leaf so does not seem to be part of this leaf mine. Any thoughts?