Thursday, 8 September 2016

Fringe on top

Another new arrival for me came a couple of nights ago - I'm sorry that I getting a bit indolent but that end-of-season feeling is creeping in.  It wasn't a new species but a form or variety of a species that I've never had before and moreover, one which the Moth Bible describes as 'rare'.

The trap had appeared to be dull as I sifted through the eggboxes, glancing wearily at hundreds of Large Yellow Underwings and Setaceous Hebrew Characters. There were one or two different moths but all them familiar: a Burnished Brass, a Brimstone moth and a Rosy Rustic.

But then I got on to the final phase of my checking, looking at the moths which had chosen the inner walls of the trap bowl to snooze on, rather than the eggboxes. Among them was a Treble-bar or Lesser Treble-bar, species which are very difficult to tell apart. And then, crouched on a plastic nut which forms some structural part of the bowl, there was the moth in my first two pictures today.

It was different from anything I've seen before; but a check with the Bible suggested that it must be the form fimbriata (fringed) of the Lesser Treble-bar. It chimed exactly with Richard Lewington's painting but because the text gave only two Oxfordshire records (1993 and 1999) I thought that I had better check with the experts on the Upper Thames Moths blog.

The prime one, Dave Wilton, unhesitatingly confirmed that I was right, and also gave me the 'fringed' translation of fimbriata, a term which also appears in Linnean names of a plant, a fish and the Broad-bordered Yellow Underwing.  His colleague Peter Hall chided me for not tempting the moth in my second picture on to a piece of glass, so that a check could be done of the end of its abdomen (home of the sexual equipment which so often defines moth species) to tell wither it was the T-b or the LT-b.

To be honest, I can't be bothered with such ways of sorting out species. Give me, any time, the approach of people such as the Dorset Moth Group whose excellent website says: 'Diagnostics include: inner dark 'bar' resembles flag and flag-pole rather than hockey-stick.' On that criterion, I would go for Lesser Treble-bar in this case. And be damned.

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