ID help requests June 2018 - part 2

[PaulHopkins]

Five years into mothing now and the subfamily Scopariinae isn't getting any easier for me. These are all from 29th June, with my best guesses after poring through the books. I'm quite prepared for any or all of my IDs to be off the mark!

Cheers
Paul

1. Eudonia lacustrata?

2. Eudonia lacustrata?

3. Eudonia lacustrata?

4. Eudonia lacustrata?

5. Eudonia mercurella?

6. Eudonia lacustrata?

[GasMacc1]

Like you, I struggle with these, so don't take this as a confirmation!

My reasoning for Photo #4 being lacustrata is (a) the marks at 2/3 are more like Greek letter alpha than simple X's and (b) there is a tiny blotch of intense white on the dorsal side of the aforementioned alphas (i.e. just inside the "tails" of the alpha) and also inside the "loop" of the alpha.

The "Common Micro-moths of Berkshire" book lists the tiny white blotch as a distinctive feature of lacustrata.

That book also gives two other ways of distinguishing mercurella from lacustrata, but I'm finding them less useful, as individual specimens might exhibit natural variation or different degrees of wear. These are the white subterminal line being unbroken in mercurella (broken in lacustrata) and the dark area (mercurella) outward of first cross-line (dark area absent in lacustrata). But the lacustrata is supposed to have dark marks outside that first cross-line - which seems to me like a "dark area".

I remain cautious of these!

[PaulHopkins]

Thanks Dave. My thought processes were similar. The Berkshire book is my first port of call for most common micros, but I also find it hard to be confident on the key features of this group. I have a particularly hard time knowing whether a line is "broken" or "unbroken", or indeed exactly where the line is!

Cheers
Paul

[johnK]

I would agree these are all lacustrata apart from no.5 which is Scoparia ambigualis.

One difference between ambigualis and mercurella is the journey of the 2nd line from the costa to dorsum. The line is more jagged and reaches the dorsum at a sharper angle in ambigualis. In mercurella this line, which is less jagged, curves more gently towards the dorsum which it reaches at close to right angles (see Manley as an example).
One can only properly judge this on the wing that it not partly cover by the other. If the wings are not overlapping then the second line forms a smooth curve across both dorsa in mercurella and lacustrata.

Hope this helps,

John

[PaulHopkins]

Thanks John. I've looked at the images in Manley with this feature in mind, and it's thoroughly lodged in my brain now!

Cheers
Paul