Buzzing with excitement after unusual-looking species

I embark on a tale of amateur research and conjecture; perhaps my readers will be recognise the creatures and inform me.
I have spent many hours poring over the evidence in books and on the internet. I cannot help but feel a certain frisson of excitement. The winged creatures I recently photographed on an offshore Kerry island would seem, by appearance, location, seasonal activity and behaviour to be one of two species listed as absent from Ireland. One of these species is so rare as to be on the endangered species list throughout its range.