Believe it or not, #LeafmineMonday is a thing on Twitter, and last Monday I read with interest this tweet, with photos, posted by Rob Edmunds (@leafminerman, one of the people behind the excellent British Leafmines website):
a sawfly mine which is fairly easy to find, made by Profenusa pygmaea. Look for brown blotches on Oak leaves but with a wriggling start as shown in the photo … Initial mines are whitish but then fade to brown.
Profenusa pygmaea is a species of sawfly – you can read more about it and see photos of the adult on the Sawflies of Britain and Ireland website. As I’m often to be found checking out Oak leaves and there were no records for this particular sawfly in my local area, of course I had to go looking, and I’ve now found these leafmines in two separate locations. I’m guessing it’s yet another under-recorded species so if you spot it in your area, do please record it.