Stream Strong-mark Foldwing Ptychoptera lacustris

So far I've only seen females of this species. It seems that females are difficult to separate from the much scarcer Black Strong-mark Foldwing Ptychoptera paludosa with absolute certainty but if I've understood things correctly an individual that looks like typical lacustris is probably safe to call lacustris. I think some lacustris can closely resemble palustris and that being the much rarer species more care is required to prove one.

This one showed extensive microtrichia on the outer half of the wing and antennal segement 3 was the same length as segments 4 and 5, which I think helps seal the deal when it comes to eliminating palustris.

female Stream Strong-mark Foldwing Ptychoptera lacustris showing wing (with close-up of outer half) and antennal segments 3-5, Wendling Beck Environment Project (Norfolk, UK), 17th May 2023

These two evaded capture so are identified from these photos alone. I think the wing-pattern is clear enough.

female Stream Strong-marked Foldwing Ptychoptera lacustris, Wendling Beck Environment Project (Norfolk, UK), 26th May 2023

female Stream Strong-mark Foldwing Ptychoptera lacustris, Pensthorpe (Norfolk, UK), 15th May 2023

Prior to finding this one I had never recorded lacustris but I had very recently found a Pond Strong-marked Foldwing Ptychoptera contaminata at exactly the same spot. I was clearly a bit careless when I processed this one as I assumed it was the same species (i.e. another contaminata), but looking back at the photos now, with the benefit of experience of the above lacustris (two of which were at the same site), I can see now that this was in fact another lacustris.

female Stream Strong-mark Foldwing Ptychoptera lacustris, Wendling Beck Environment Project (Norfolk, UK), 2nd June 2022